Chirality-Induced Spin Selectivity -- Articles & patents

Chirality-Induced

Spin Selectivity ( CISS )

Related: https://www.youtube.com/watch?v=uO3gojBAqsg&t=1055s *KITA, Ron : Chiralex Gravity Shield* ... US8901943 -- Gravitational Attenuating Material GREBBENIKOV, Viktor : Insect AntiGravity (1)  ( 2 )

https://en.wikipedia.org/wiki/Chirality-induced_spin_selectivity Chirality-induced spin selectivity (CISS) refers to multiple phenomena where the chirality of a chemical compound influences the spin of transmitted or emitted electrons. This effect was discovered by Ron Naaman and co-workers.[1]

Experiments were able to demonstrate the effect in the form of polarization of electrons scattered from chiral molecules, spin-dependent transmission probabilities through layers of chiral molecules, spin-selectivity of electron-transport in a chiral medium and enantio-selectivity in chemical reactions induced by spin-polarized electrons.[2]

Theoretical models were able to qualitatively explain the effect using spin-orbit coupling (SOC). But quantitatively, the predicted effect was always orders of magnitude smaller than what was measured in experiments. Whilst mechanism underlying CISS is not completely understood, a hybrid method comprising a film of pure gold with chiral molecules on it has produced results on par with the magnetic method.[3]

In 2025, Huang et al. reported voltage-controlled interfacial chirality in an otherwise achiral molybdenum disulfide surface by using an electric double-layer transistor with enantiopure ionic liquids; the induced state was detected through CISS and the electrical magnetochiral effect.[4]

References Ray, K; Ananthavel, SP; Waldeck, DH; Naaman, R (February 1999). "Asymmetric scattering of polarized electrons by organized organic films of chiral molecules". Science. 283 (5403): 814–816. doi:10.1126/science.283.5403.814.

Evers, Ferdinand; Aharony, Amnon; Bar-Gill, Nir; Entin-Wohlman, Ora; Hedegård, Per; Hod, Oded; Jelinek, Pavel; Kamieniarz, Grzegorz; Lemeshko, Mikhail; Michaeli, Karen; Mujica, Vladimiro; Naaman, Ron; Paltiel, Yossi; Refaely-Abramson, Sivan; Tal, Oren (April 2022). "Theory of Chirality Induced Spin Selectivity: Progress and Challenges". Advanced Materials. 34 (13) 2106629. arXiv:2108.09998. Bibcode:2022AdM....3406629E. doi:10.1002/adma.202106629.

"The Quantum Twist: Scientists Unlock a New Way to Control Electrons". January 31, 2025.

Huang, Po-Jung; Ando, Yoshio; Tanaka, Miuko; Nishio, Yukito; Ideue, Toshiya; Taniguchi, Kouji (21 November 2025). "Proximity-induced chirality at the achiral conductive interface by electrical control of enantiopure ion adsorption". Science Advances. 11 (47) eadx2281. doi:10.1126/sciadv.adx2281.

https://www.weizmann.ac.il/sites/CISS/ The CISS Effect

Welcome toThe CISS EffectCommunity...

https://www.youtube.com/shorts/p3lde7wTmmg

https://www.youtube.com/watch?v=VKEZSfuMgL0

Chiral-induced Spin Selectivity // A Course on Abiogenesis by Dr. James Tour In this episode, Dr. James Tour analyzes a false claim of molecular homochiral evolution, asking, in one example, how proteins could become homochiral when no prebiotically relevant route has been shown to synthesize, separate, or polymerize homochiral amino acids. Furthermore, a discussion on the possibility of racemic molecules in cells takes place. Finally, the amazing phenomenon of chiral-induced spin selectivity (CISS) is introduced, and Dr. Tour shows us how this enables the cell to be the amazing efficient machine that it is.

https://www.weizmann.ac.il/sites/CISS/publications The CISS Effect

Welcome toThe CISS EffectCommunity...

https://pubs.acs.org/chreay/article/124/4/1950/154894/Chiral-Induced-Spin-Selectivity Chiral Induced Spin Selectivity Brian P. Bloom, et al.

[ PDF ] Abstract -- Since the initial landmark study on the chiral induced spin selectivity (CISS) effect in 1999, considerable experimental and theoretical efforts have been made to understand the physical underpinnings and mechanistic features of this interesting phenomenon. As first formulated, the CISS effect refers to the innate ability of chiral materials to act as spin filters for electron transport; however, more recent experiments demonstrate that displacement currents arising from charge polarization of chiral molecules lead to spin polarization without the need for net charge flow. With its identification of a fundamental connection between chiral symmetry and electron spin in molecules and materials, CISS promises profound and ubiquitous implications for existing technologies and new approaches to answering age old questions, such as the homochiral nature of life. This review begins with a discussion of the different methods for measuring CISS and then provides a comprehensive overview of molecules and materials known to exhibit CISS-based phenomena before proceeding to identify structure–property relations and to delineate the leading theoretical models for the CISS effect. Next, it identifies some implications of CISS in physics, chemistry, and biology. The discussion ends with a critical assessment of the CISS field and some comments on its future outlook.

Visual Abstract

https://www.nature.com/articles/s43246-026-01272-0 Chiral-induced spin selectivity in chiral solid-state materials for biomedical engineering Rui Gao, Dan Meng & Xiongbin Lu

Chirality-induced spin selectivity (CISS) refers to multiple phenomena where the chirality of a chemical compound influences the spin of transmitted or emitted electrons. This effect was discovered by Ron Naaman and co-workers.[1]

Experiments were able to demonstrate the effect in the form of polarization of electrons scattered from chiral molecules, spin-dependent transmission probabilities through layers of chiral molecules, spin-selectivity of electron-transport in a chiral medium and enantio-selectivity in chemical reactions induced by spin-polarized electrons.[2]

Theoretical models were able to qualitatively explain the effect using spin-orbit coupling (SOC). But quantitatively, the predicted effect was always orders of magnitude smaller than what was measured in experiments. Whilst mechanism underlying CISS is not completely understood, a hybrid method comprising a film of pure gold with chiral molecules on it has produced results on par with the magnetic method.[3]

In 2025, Huang et al. reported voltage-controlled interfacial chirality in an otherwise achiral molybdenum disulfide surface by using an electric double-layer transistor with enantiopure ionic liquids; the induced state was detected through CISS and the electrical magnetochiral effect.[4]

https://www.nature.com/articles/s43246-026-01272-0 Chiral-induced spin selectivity in chiral solid-state materials for biomedical engineering Rui Gao, Dan Meng & Xiongbin Lu

Chirality-induced spin selectivity (CISS) refers to multiple phenomena where the chirality of a chemical compound influences the spin of transmitted or emitted electrons. This effect was discovered by Ron Naaman and co-workers.[1]

Experiments were able to demonstrate the effect in the form of polarization of electrons scattered from chiral molecules, spin-dependent transmission probabilities through layers of chiral molecules, spin-selectivity of electron-transport in a chiral medium and enantio-selectivity in chemical reactions induced by spin-polarized electrons.[2]

Theoretical models were able to qualitatively explain the effect using spin-orbit coupling (SOC). But quantitatively, the predicted effect was always orders of magnitude smaller than what was measured in experiments. Whilst mechanism underlying CISS is not completely understood, a hybrid method comprising a film of pure gold with chiral molecules on it has produced results on par with the magnetic method.[3]

In 2025, Huang et al. reported voltage-controlled interfacial chirality in an otherwise achiral molybdenum disulfide surface by using an electric double-layer transistor with enantiopure ionic liquids; the induced state was detected through CISS and the electrical magnetochiral effect.[4]

Patents

SINGLE-PHOTON GENERATOR INCLUDING METAL NANOPARTICLES HAVING CHIRAL STRUCTURE AND TWO-DIMENSIONAL TRANSITION METAL DICHALCOGENIDE LAYER AND MANUFACTURING METHOD THEREOF WO2026100850 Construction

method of self-similar structure two-dimensional chiral metamaterial with sound insulation and shock absorption functions CN122245538 Composite flapping wing structure based on chiral/anti-chiral core layer CN122009454 Multi-directional

impact-resistant paper-cut-origami synergistic metamaterial CN122014779 Design method of disordered multifunctional metamaterial structure with low-frequency vibration isolation and negative Poisson's ratio effects CN121963984 Tetra-chiral structure-based flexoelectric metamaterial CN121922271 Different-chirality

spliced variable-stiffness negative poisson ratio metamaterial structure CN121897689 Rigidity-variable

compression-torsion chiral metamaterial cell element based on integrated molding CN121854550 Efficient three-dimensional spiral metamaterial optical device for chiral resolution of vortex beam CN121784870 Novel reinforced hollow blade filled with chiral metamaterial lattice structure CN121676478 Chiral liquid crystal superstructure for luminous object charge regulation and control and preparation method and application of chiral liquid crystal superstructure CN121673652 Vanadium dioxide-based terahertz broadband chiral absorber capable of being actively regulated and controlled CN121584271 Chiral metamaterial vibration reduction structure for high-speed train floor and preparation method of chiral metamaterial vibration reduction structure CN121520328 Tunable narrow-band chiral metamaterial surface based on silicon and germanium antimony tellurium composite nanostructure CN121522909 Tuned mass inertial damper of arch bridge suspender and optimization design method of tuned mass inertial damper CN121473229 Tuned mass inertial torsional damper for rigid suspender of arch bridge and optimization design method thereof CN121451498 Bifunctional chiral super-structure surface capable of switching polarization conversion and wave absorption CN121332179 Ternary coupling enhanced perovskite chiral metamaterial and preparation system and method thereof CN121248153 Chiral composite negative Poisson's ratio metamaterial CN121111926 Star-shaped chiral impact-resistant energy-absorbing metamaterial and adjustment method of metamaterial structure CN120946728 Curvature rod piece structure design method and system and rod piece structure application CN120911031 Negative Poisson's ratio metamaterial wedge-shaped bottom CN120828905 Aperiodic chiral mechanical metamaterial implementation method CN120781587 Chiral metamaterial absorber for multifunctional sensing and preparation method thereof CN120779504 Negative Poisson's ratio mechanical metamaterial anti-collision energy-absorbing device CN223411334 Electromagnetic wave absorber with wave-transparent window capable of being dynamically opened and closed CN223285279 Lightweight helicopter undercarriage based on mechanical metamaterial CN120482348 Total space vector vortex generator CN120262026 Energy-absorbing three-dimensional metamaterial with interactively combined positive and negative Poisson's ratio structures CN120212178 Anti-tri-chiral structure-based flexoelectric metamaterial CN120145772 Chiral metamaterial sensor based on vanadium dioxide CN120142235 Two-dimensional light path device based on hyperbolic anisotropic metamaterial CN120065383 Flexible chiral metasurface with tunable circular dichroism and polarization conversion function CN119944313 Damping wheel of auxetic metamaterial sandwich thickness gradient structure CN119911034 Chiral transmission device based on metamaterial waveguide CN119556379 Metamaterial cell based on independent chiral distortion unit and metamaterial structure CN119508403 Pressure contact type chiral-negative Poisson's ratio regulation and control acoustic metamaterial CN119479600 Manufacturing method for space station protection structure and space station protection structure CN119427808 Design method of spin selective absorption switch based on three-dimensional chiral metamaterial CN119401137 Absorption and transmission integrated metamaterial structure with wave-transparent window capable of being dynamically opened and closed CN119297612 Topological chiral vibration reduction metamaterial structure controlled by gyroscope CN118998251 Manufacturing method of metamaterial using deformation of nucleic acid origami structure KR20240160417 Variable stiffness unit, variable stiffness metamaterial and mechanical metamaterial CN118815892 Self-balancing chiral metamaterial pipeline for low-frequency vibration isolation CN118669642 Chiral-rhombic mechanical metamaterial based on mass amplification CN118629378 Total-space transmission and reflection integrated multifunctional passive super-structure surface CN118523089 Bionic metamaterial wide-spectrum polarized photoelectric detection integrated assembly and preparation method thereof CN118366977 4D printing chiral superstructure heterogeneous stacked anisotropic deformable bearing structure CN118287674 Three-dimensional

four-chiral pressure-torsion metamaterial structure and manufacturing method thereof CN118274058 Holographic metamaterial negative film and preparation system and method of holographic metamaterial optical device CN118259511 Electric tower anti-collision device based on chiral mechanical metamaterial CN117845805 Anti-chiral metamaterial research method based on NSGA-II optimization algorithm CN117831679 Dual-band polarization converter based on chiral metasurface CN117767017 Sole, performance adjusting method thereof and sports shoes CN117322702 PHOTODETECTOR PIXEL, PHOTODETECTOR AND METHODS OF FORMING THE SAME US202528376 Preparation method and application of metal detection wafer CN117042573 Nano-scale chiral Swiss roll array continuous film, preparation method and application of nano-scale chiral Swiss roll array continuous film in polarization sensitive photocatalysis CN116904932 Bionic net-shaped metamaterial based on three-dimensional horseshoe-shaped microstructure CN116753449 Mechanical property database and numerical calculation method based on chiral lattice structure CN116721722 Preparation method of laser direct writing type chiral terahertz metamaterial based on graphene film CN116565571 Torsion angle measuring clamp for compression torsion mechanical test of chiral mechanical metamaterial CN116026678 Electric power equipment real-time high temperature early warning system based on tubular chiral thermodynamic metamaterial CN115824440 Chiral mechanical metamaterial structure with compression torsion coupling and swelling torsion coupling CN115750643 A MECHANICAL METAMATERIAL WITH IMPROVING COMPRESSIVE RESPONSES TWI793952 Chiral mechanical metamaterial sandwich structure without torsion size effect and application thereof CN115691719 Frequency selective surface based on continuous fiber 3D printing and design and manufacturing method CN115513668 Discrete macroscopic metamaterial systems US2022290570 Chiral metamaterial unit and array for tunable multi-polarization conversion CN115020988 Chiral metamaterial unit and array capable of tuning linear circular polarization conversion CN115020989 Dual-frequency, dual-circular-polarization and high-isolation Fabry-Perot cavity MIMO antenna and processing method thereof CN114843772 Underwater sound insulation metamaterial based on chiral structure CN114724536 Optical diode based on asymmetric reflection of single-layer external chiral metasurface CN114236648 Chiral serine identification method based on S-shaped mirror image structure terahertz metamaterial CN114034659 NONMAGNETIC WAVEGUIDE TYPE ISOLATOR JP2021193437 Structural design method of chiral acoustic metamaterial plate CN113806975 Three-dimensional

chiral acoustic metamaterial with high bearing capacity and low broadband vibration suppression performance CN113808562 PLASMONIC META-SURFACE BASED MOLECULAR SENSORS AND METHODS FOR MAKING AND USING THEM US2021373009 Z-shaped compression-torsion metamaterial structure CN214226520 Chiral metamaterial circular polarization laser CN113381277 Convertible external chiral terahertz metamaterial unit and device based on vanadium dioxide CN113285232 Dynamic polarization regulation and control device based on anisotropic chiral metamaterial CN113267901 Carbon matrix spiral chiral sequence metamaterial with abnormal ferromagnetic property and preparation method and application thereof CN112938928 Lattice structure design for buckling driving large-angle torsion CN112836250 Z-shaped compression-torsion metamaterial structure CN112820362 Spatial chiral compression-torsion super-structure material CN112693108 Polarization device based on diffraction chiral metamaterial and preparation method thereof and optoelectronic device CN112630869 Micro-cavity with chiral polarization selectivity as well as preparation method and application thereof CN112558294 Design method of chiral metamaterial structure with predetermined negative Poisson's ratio characteristic CN112307663 Chiral auxetic metamaterial structure with compression-shear coupling characteristic and preparation method thereof CN112045990 Chiral auxetic metamaterial structure with tension-torsion coupling characteristics and preparation method thereof CN112049886 Controllable chiral structure based on GST phase change material temperature control and control method CN111965849 Metamaterial polarization conversion device with chiral optical activity CN111948750 Chiral metamaterial structure with asymmetric transmission characteristic and design method CN111817013 Terahertz chiral metamaterial wave absorber with flexible substrate and manufacturing method CN111490355 Integrated high extinction ratio infrared circular polarization detector and design method CN111293188 Medium-infrared-band

double-channel multi-information chiral tunable graphene metamaterial CN110441926 Three-dimensional

chiral spherical structure, metamaterial and use method thereof CN110299617 Refractive index sensor and preparation method thereof CN110186872 Novel three-dimensional cellular metamaterial with local tension-torsion coupling effect CN109822981 Chiral microwave absorbing metamaterial and preparation and application thereof CN109786973 Method for calculating spontaneous emission rate of two-level atoms near chiral metamaterial interface CN109273057 Adjustable chiral unit, metamaterial and application method based on pin diode CN109256621 Vibration absorber based on tension-torsion coupling metamaterial structure CN108386472 QUASI-PLANAR CHIRAL METAMATERIAL KR20180085314 Super material structure of glassy metal with chirality micro -structure CN206799718 Metal glass metamaterial with chiral microstructure CN107012409 Intrinsic electromagnetic metamaterial meta-surface capable of supporting TE (transverse electric) surface waves and TM (transverse magnetic) surface waves CN106684569 Microwave band dual-layer metal wire structural chirality super surface CN106058477 MESHED CHIRAL METAMATERIAL KR20160113339 LEFT-HANDED CIRCULAR POLARISATION CONVERSION METAMATERIAL THIN FILM WO2017020792 Chiral metamaterial micro unit structure with 90-degree polarization deflection characteristic CN105140652 Gradually varied spiral metal chiral metamaterial circular polarizer CN105137520 RIGHT-HANDED CIRCULAR POLARISATION CONVERSION METAMATERIAL THIN FILM WO2017020791 Circularly-polarized

horn antenna based on C waveband CN104953293 Spiral-like metal chiral metamaterial circular polarizer CN104865628 Double-L-shaped chiral metamaterial micro-unit structure with asymmetric transmission feature CN104600434 Circular dichroism method and apparatus using negative index metamaterials KR101494326 Microwave frequency band three-frequency-point polarization-independent 90-degree polarized revolver and application thereof CN103715477 DOPED CHIRAL POLYMER METAMATERIALS US2014017480 GYROTROPIC METAMATERIAL STRUCTURE WO2013010071

*** ACTIVE CHIRAL PHOTONIC METAMATERIAL US2011141541 Chiral Metamaterials US2010141358

MagnetoOptics

/Gyroptics

\\*\ Wikipedia.org Magneto-optic effect

A magneto-optic effect is any one of a number of phenomena in which an electromagnetic wave propagates through a medium that has been altered by the presence of a quasistatic magnetic field. In such a medium, which is also called gyrotropic or gyromagnetic, left- and right-rotating elliptical polarizations can propagate at different speeds, leading to a number of important phenomena. When light is transmitted through a layer of magneto-optic material, the result is called the Faraday effect: the plane of polarization can be rotated, forming a Faraday rotator. The results of reflection from a magneto-optic material are known as the magneto-optic Kerr effect (not to be confused with the nonlinear Kerr effect).

In general, magneto-optic effects break time reversal symmetry locally (i.e., when only the propagation of light, and not the source of the magnetic field, is considered) as well as Lorentz reciprocity, which is a necessary condition to construct devices such as optical isolators (through which light passes in one direction but not the other).

Two gyrotropic materials with reversed rotation directions of the two principal polarizations, corresponding to complex-conjugate ε tensors for lossless media, are called optical isomers...

https://journals.aps.org/prl/abstract/10.1103/vxtm-kgrx Phys. Rev. Lett. 135, 246704 – Published 12 December, 2025 DOI: https://doi.org/10.1103/vxtm-kgrx Gyrotropic Magnetic Effect in Metallic Chiral Magnets

Nisarga Paul, Takamori Park, Jung Hoon Han, and Leon Balents Abstract --We study the gyrotropic magnetic effect (GME), the low-frequency limit of optical gyrotropy, in metals and semimetals coupled to chiral spin textures. In these systems, the chiral spin texture which lacks inversion symmetry can imprint itself upon the electronic structure through Hund’s coupling, leading to novel low-frequency optical activity. Using perturbation theory and numerical diagonalization of both relativistic and nonrelativistic models of conduction electrons coupled to spin textures, we analyze how the GME manifests in both single-𝑞

and multi-𝑞 textures. Analytical expressions for the rotatory power are derived in terms of universal scaling functions. Estimates based on realistic material parameters reveal an experimentally viable range of values for the rotatory power. The GME arises from the orbital and spin magnetic moments of conduction electrons, with the orbital part closely tied to Berry curvature and playing a significant role in relativistic metals but not so in nonrelativistic metals where there is no inherent Berry curvature. The spin contribution to the GME can be significant in nonrelativistic metals with a large Fermi energy. Our Letter shows that the GME can be a sensitive probe of magnetic chirality and symmetry breaking in metallic chiral magnets.

https://arxiv.org/abs/2601.04787 Intrinsic Gyrotropic Magnetic Current of Orbital Origin Koushik Ghorai, Sankar Sarkar, Amit Agarwal Abstract -- In

gyrotropic crystals, an oscillating magnetic field induces a charge response known as the gyrotropic magnetic current. While its conventional origin is attributed to magnetic field modified band energy and shift in the Fermi-surface, a recent study identified an additional spin-driven magnetic displacement contribution. Here, we complete the picture by identifying the orbital counterpart of the magnetic displacement current. Using a density-matrix formulation that incorporates both minimal coupling and spin-Zeeman interactions, we derive the electronic equations of motion in the presence of an oscillating magnetic field and uncover a previously unexplored orbital contribution to the wavepacket velocity. Physically, this contribution arises from the time variation of the magnetic-field induced charge polarization. In the low frequency transport regime, this mechanism becomes purely intrinsic. We illustrate this intrinsic gyrotropic current of orbital origin in the PT-symmetric antiferromagnet CuMnAs. We show that the intrinsic gyrotropic magnetic current reverses sign upon Néel vector reversal, establishing it as a direct probe of antiferromagnetic order in CuMnAs and other PT-symmetric antiferromagnets.

https://www.nature.com/articles/s41598-023-48503-9 Scientific Reports volume 13, Article number: 21986 (2023) Giant enhancement of nonreciprocity in gyrotropic heterostructures Ioannis Katsantonis, Anna C. Tasolamprou, Thomas Koschny, Eleftherios N. Economou, Maria Kafesaki & Constantinos Valagiannopoulos Abstract --Nonreciprocity is a highly desirable feature in photonic media since it allows for control over the traveling electromagnetic waves, in a way that goes far beyond ordinary filtering. One of the most conventional ways to achieve nonreciprocity is via employing gyrotropic materials; however, their time-reversal-symmetry-breaking effects are very weak and, hence, large, bulky setups combined with very strong magnetic biases are required for technologically useful devices. In this work, artificial heterostructures are introduced to enhance the effective nonreciprocal behavior by reducing the contribution of the diagonal susceptibilities in the collective response; in this way, the off-diagonal ones, that are responsible for nonreciprocity, seem bigger. In particular, alternating gyrotropic and metallic or plasmonic films make an epsilon-near-zero (ENZ) effective-medium by averaging the diagonal permittivities of opposite sign, representing the consecutive layers. The homogenization process leaves unaltered the nonzero off-diagonal permittivities of the original gyrotropic substance, which become dominant and ignite strong nonreciprocal response. Realistic material examples that could be implemented experimentally in the mid-infrared spectrum are provided while the robustness of the enhanced nonreciprocity in the presence of actual media losses is discussed and bandwidth limitations due to the unavoidable frequency dispersion are elaborated. The proposed concept can be extensively utilized in designing optical devices that serve a wide range of applications from signal isolation and wave circulation to unidirectional propagation and asymmetric power amplification.

https://meep.readthedocs.io/en/latest/Scheme_Tutorials/Gyrotropic_Media/ Gyrotropic Media

In this example, we will perform simulations with gyrotropic media. See Materials for more information on how gyrotropy is supported....

Gyrotropic Crystals as a Basis for Creation of Helical Polychromatic Singular Beams by Yuriy Egorov and Alexander Rubass [ PDF ] Abstract --In this work, studies are carried out in the field of optical singular beams that have passed through gyrotropic crystals. We have experimentally shown that singular beams with a helical intensity distribution are formed when passing through a system of two gyrotropic crystals with opposite values of the gyration coefficient. It is shown that the system is capable of generating optical vortices with a double topological charge in one of the components of circular polarization when light propagates through two gyrotropic crystals.

https://ui.adsabs.harvard.edu/abs/2022APS..DPPPO7003R/abstract Topological Edge States in Tunable Bulk Gyrotropic Media Composed of Magnetized Low-Temperature Plasma Discharges Rodriguez, Jesse ; Houriez, Luc ; Mehrpour-Bernety, Hossein ; Cappelli, Mark Abstract -- Gyrotropic

media exhibit several interesting electromagnetic properties, including topologically protected edge states that allow for one-way, back-scattering immune propagation of interfacial electromagnetic waves. Unfortunately, such media are challenging to create for engineering applications since the use of ferromagnetic (gyrotropic) materials limit the range of operating frequencies and a homogeneous bulk magnetized plasma is difficult to produce in practice. In this presentation, we show how a tunable bulk gyrotropic medium can be constructed using magnetized low-temperature plasma discharge tubes in a two-dimensional photonic crystal configuration. Experiments are performed for microwave frequencies in the range of 2-10 GHz. Band structures for both the magnetized and unmagnetized case are compared and confirmed via experimental transmission measurements and numerical simulations of the actual device. Evidence for topologically-protected edge states from local field measurements is presented.

https://www.chess.cornell.edu/spontaneous-gyrotropic-electronic-order-1-tise2 Spontaneous Gyrotropic Electronic Order in 1?-TiSe₂ Elke Arenholz, CHESS Abstract --  ..Now, a team of researchers lead by Nuh Gedik’s group (MIT) have demonstrated spontaneous chiral symmetry breaking by electrons in a material called 1T-TiSe2, despite its non-chiral crystal structure. They employed a new measurement technique, the “circular photogalvanic effect”: A change in photocurrent is measured when the helicity of light is flipped, which can only occur if the electrons in the material are chiral.

https://pubmed.ncbi.nlm.nih.gov/32103195/ Nature. 2020 Feb;578(7796):545-549. doi: 10.1038/s41586-020-2011-8. Epub 2020 Feb 26. Spontaneous

gyrotropic electronic order in a transition-metal dichalcogenide Su-Yang Xu et al Abstract -- Chirality is ubiquitous in nature, and populations of opposite chiralities are surprisingly asymmetric at fundamental levels1,2. Examples range from parity violation in the subatomic weak force to homochirality in biomolecules. The ability to achieve chirality-selective synthesis (chiral induction) is of great importance in stereochemistry, molecular biology and pharmacology2. In condensed matter physics, a crystalline electronic system is geometrically chiral when it lacks mirror planes, space-inversion centres or rotoinversion axes1. Typically, geometrical chirality is predefined by the chiral lattice structure of a material, which is fixed on formation of the crystal. By contrast, in materials with gyrotropic order3-6, electrons spontaneously organize themselves to exhibit macroscopic chirality in an originally achiral lattice. Although such order-which has been proposed as the quantum analogue of cholesteric liquid crystals-has attracted considerable interest3-15, no clear observation or manipulation of gyrotropic order has been achieved so far. Here we report the realization of optical chiral induction and the observation of a gyrotropically ordered phase in the transition-metal dichalcogenide semimetal 1T-TiSe2. We show that shining mid-infrared circularly polarized light on 1T-TiSe2 while cooling it below the critical temperature leads to the preferential formation of one chiral domain. The chirality of this state is confirmed by the measurement of an out-of-plane circular photogalvanic current, the direction of which depends on the optical induction. Although the role of domain walls requires further investigation with local probes, the methodology demonstrated here can be applied to realize and control chiral electronic phases in other quantum materials4,16.

opg.optica.org/oe/fulltext.cfm?uri=oe-33-12-24370c Magnet-less gyrotropy using time-periodic modulation of permittivity Somayeh Boshgazi, Khashayar Mehrany, and Mohammad Memarian [ PDF ] Abstract -- Time-varying

(TV) media in electromagnetics have unlocked new paths to important electromagnetic effects such as non-reciprocity, frequency conversion, and parametric amplification. In light of such advances over the past decade, a curious question arises as to whether chirality or/and gyrotropy, may also be achieved using TV dielectrics. In this paper, we propose a suitable time-modulation of the permittivity tensor in a static achiral and non-gyrotropic crystal and thereby emulate gyrotropy without the need of magnetic materials and external magnetic bias field. The emulated gyrotropy is owed to the temporal rotation of the principal axes of the permittivity tensor, which sustains only circularly/elliptically polarized eigenmodes. A possible realization using modulated electro-optic effects in a nonlinear crystal is proposed, showing a feasible approach to realize gyrotropy by time variation in non-magnetic achiral media.

https://journals.iucr.org/paper?a18430 Acta Cryst. (1980). A36, 760-762 https://doi.org/10.1107/S0567739480001532 The acoustic gyrotropic tensor in crystals K. Kumaraswamy and N. Krishnamurthy Abstract

-- The acoustic gyrotropic tensor is a fifth-rank tensor characterized by dij, l = -dji, l, with i, j = 11, 22, 33, (23, 32), (31, 13), (12, 21), l = 1, 2, 3, and controls the acoustical activity in crystals. With the employment of group theoretical methods, the number of independent coefficients of this tensor and the character for this tensor under proper and improper rotation are worked out. A classification of the acoustically active classes is given.

https://scipost.org/SciPostPhys.16.2.055/pdf Nonreciprocal superconducting transport and the spin Hall effect in gyrotropic structures Tim Kokkeler, Ilya Tokatl, F. Sebastian BergeretAbstract -- The search for superconducting systems exhibiting nonreciprocal transport and, specifically, the diode effect, has proliferated in recent years. This trend has encompassed a wide variety of systems, including planar hybrid structures, asymmetric SQUIDs, and certain noncentrosymmetric superconductors. A common feature of such systems is a gyrotropic symmetry, realized on different scales and characterized by a polar vector. Alongside time-reversal symmetry breaking, the presence of a polar axis allows for magnetoelectric

effects, which, when combined with proximity-induced superconductivity,

results in spontaneous non-dissipative currents that underpin the superconducting diode effect. With this symmetry established, we present a comprehensive theoretical study of transport in a lateral Josephson junction composed of a normal metal support- ing the spin Hall effect, and attached to a ferromagnetic insulator. Due to the presence of the latter, magnetoelectric effects arise without requiring external magnetic fields. We determine the dependence of the anomalous currents on the spin relaxation length

and the transport parameters commonly used in spintronics to characterize the interface between the metal and the ferromagnetic insulator. Therefore, our theory naturally unifies nonreciprocal transport in superconducting systems with classical spintronic effects, such as the spin Hall effect, spin galvanic effect, and spin Hall magnetoresistance. We propose an experiment involving measurements of magnetoresistance in the normal state and nonreciprocal transport in the superconducting state. Such experiment would, on the one hand, allow for determining the parameters of the model and thus verifying with a greater precision the theories of magnetoelectric effects in normal systems. Ons the other hand, it would contribute to a deeper understanding of the underlying microcopic origins that determine these parameters.

https://www.worldscientific.com/doi/pdf/10.1142/9789812709547_0024?download=true&srsltid=AfmBOoqNrqOpEFuxYAi4OhQ3xdAfUnvo9Xv5qvI6FTSuK-i3T5Dro9YP https://doi.org/10.1142/9789812709547_0024 Distinctive

feature of 1D anisotropic and gyrotropic photonic crystals Alexey P. Vinogradov et al Abstract:--The magneto-optical properties of 1D photonic crystals (PC) are considered. The consideration is focused on the distinctive features of 1D PCs because any devices made on the base of 1D PC are more robust for losses than those employing 2D or 3D PC. To make better off the properties of comparative simple 1D geometry we suggest the usage of anisotropic and gyrotropic materials. Firstly, such PCs exhibit new physical phenomena, namely, formation of the Yeh band gaps, magnetooptical and birefringence effects. Secondly, since the anisotropy and gyrotropy are easy caused by the external electric and magnetic fields the new properties of the PCs are tunable. The functioning of switchable filter, magnetic superlens and other devices are considered.

https://openurl.ebsco.com/EPDB%3Agcd%3A14%3A23004686/detailv2?sid=ebsco%3Aplink%3Acrawler-gcd&id=ebsco%3Agcd%3A162435617&crl=c&jrnl=00213640&link_origin=none Gyrotropic Oscillations of Magnetic Vortices in Two Interacting Ferromagnetic Disks. Skorokhodov, E. V.; Tatarskiy, D. A.; Gorev, R. V.; Mironov, V. L.; Fraerman, A. A.Abstract -- The gyrotropic motion of vortex magnetization distributions in two coupled ferromagnetic disks has been experimentally studied and numerically simulated. The dependence of the resonant frequency of the collective gyrotropic oscillation mode of vortices on the distance between the centers of disks has been studied by magnetic resonance force spectroscopy. The energy of the interaction of magnetic vortices as a function of the distance between disks has been estimated from this dependence using solutions of the Thiele equation.