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TaS₂ can be synthesised in the 4Hb stacking, a natural heterostructure of “H" and “T"-type layers, which exhibits several unusual phenomena in its low temperature superconducting phase. Here, its layer-dependent electronic properties are explored, revealing the T layers are effectively insulating in the bulk, though not at the surface.

Generation of orbital currents in a non-magnetic material can be useful to build efficient orbitronic devices. Now, the interplay of chiral phonons and electrons is shown to produce orbital currents in α-quartz.

Interwoven magnetic and non-magnetic layers in TbTi₃Bi₄ overcome kagome frustration, producing coupled elliptical-spiral magnetic and spin-density-wave orders and a very large anomalous Hall effect driven by strong electron–magnetic field interactions.

Materials which simultaneously exhibit superconductivity and topologically non-trivial electronic band structure possess potential applications in quantum computing but have yet to be found. Here, the authors find superconductivity in MoTe₂, a material predicted to be topologically non-trivial.

Layering quantum materials can produce interesting phenomena by combining the different behaviour of electronic states in each layer. A layer-sensitive measurement technique provides insights into the physics of a magnetic topological insulator.

The magnetoresistance suggests an exotic topological phase in LaBi, but the evidence is still missing. Here, Nayaket al. report the existence of surface states of LaBi through the observation of three Dirac cones, confirming it a topological semimetal.

Electrical tuning of the recombination zone in circularly polarized (CP) OLEDs enables switching the CP generation mechanism between normal and anomalous CP electroluminescence. This is exploited to electrically control the handedness of emitted CP light from the same device with the same enantiomer material.

Non-reciprocal charge transport refers to the different resistance between positive and negative current, and is fundamental in a variety of applications, for instance, current rectification. Some materials exhibit intrinsic nonreciprocal transport, but manipulation of this can be challenging. Here, the authors demonstrate large non-reciprocal transport which can be switched magnetically, is stacking dependent, and can be tuned via an applied gate voltage.

An atomically thin high-κ gate dielectric of Bi₂SeO₅ can be formed via layer-by-layer oxidization of an underlying two-dimensional semiconductor, allowing high-performance field-effect transistors and inverters to be fabricated.

Berry curvature sits at the heart of both the anomalous hall effect and topological hall effect, with the former arising from a momentum space berry curvature, while the latter arises from a real space berry curvature. Here, Li et al present an intriguing example of a combined real and reciprocal space berry curvature in the kagome material Mn3Sn, resulting in a large field linear anomalous Hall effect.

The nature of unconventional charge density wave in kagome metals is currently under intense debate. Here the authors report the coexistence of the 2 × 2 × 1 charge density wave in the kagome sublattice and the Sb 5p-electron assisted 2 × 2 × 2 charge density waves in CsV₃Sb₅.

In Bi₂O₂Se thin films, the local inversion-symmetry breaking in two sectors of the [Bi₂O₂]²⁺ layer yields opposite Rashba spin polarizations, which compensate each other and give rise to the hidden Rashba effect. Hence, the films exhibit only even-integer quantum Hall states, but there is no sign of odd-integer states.

Some chiral molecules can produce a giant spin polarization, a feature termed chirality-induced spin selectivity. The origin of this has been hotly debated. In this theory work, Zhao, Zhang and coauthors propose that the origin of the effect lies in charge trapping induced barrier modification, termed magnetochiral charge pumping.

Oxygen evolution is a key reaction in electrolysers and involves a spin-dependent, multi-electron transfer process. Here the authors use topological semimetals with intrinsic chirality as a means to control spin in oxygen evolution catalysts, and explore the role of spin–orbit coupling in determining activity.

The mechanism of the charge density wave in kagome metals is not fully understood. Here, the authors report the observation of unusual large-frequency collective lattice excitations, or amplitude modes, in CsV₃Sb₅ in the absence of phonon mode softening, evidencing the strong electron-phonon coupling regime.

In most metals the optical Hall effect is very small at visible wavelengths, and usually can only be observed at low frequencies. Here, Am-Shalom et al present a technique involving a large amplitude modulation of the external magnetic field, allowing for the measurement of the optical Hall effect in a range of metals at visible wavelengths.

Domain wall formation and propagation using a small electric voltage are demonstrated in ferro-rotational 1T-TaS₂, although the ferroic order does not couple with electromagnetic fields, providing an opportunity for the manipulation and application of ferro-rotational order.

Quantum-metric-induced nonlinear transport, including the nonlinear anomalous Hall effect and a diode-like response, is observed in thin films of a topological antiferromagnet, providing a means to design magnetic nonlinear devices.

Nonlinear transport effects arising from the quantum metric have been reported in topological magnets at low temperatures. Here, the authors demonstrate a second-harmonic transport response in TbMn₆Sn₆ at room temperature, attributed to the quantum metric and controllable via an applied magnetic field.

Chirality induced spin selectivity is a process whereby a chiral molecule induces a spin-polarization to a current passing along the chiral molecule. The exact physical origin of the effect is still debated despite extensive experimental result. Here, Adhikari et al provide evidence for the important role of spin-orbit coupling in the normal metals that connect to the chiral molecule in CISS experiments.

The surfaces of noble metals possess Shockley states which exhibit Rashba-type spin splitting and spin-momentum locking. Here, the authors use ab initiomethods and photoemission spectroscopy to demonstrate how such Shockley states may be reinterpreted as topologically protected surface states.

Careful measurements of the zero-field quantum anomalous Hall effect find a less-precisely-quantized Hall conductivity than the integer quantum Hall effect. Here, the authors theoretically study the effects of nonlinear corrections to the Hall conductivity in both topological and trivial magnetic insulators.

Charge-to-spin conversion is critical element for spintronic devices. In most materials, there are several sources of charge-to-spin conversion, which are often challenging to disentangle. Here, Chen et al succeed in disentangling spin Hall and Rashba-Edelstein contributions to charge-to-spin conversion in ultrathin MoTe2 using position dependent measurements of the current-induced spin accumulation.

The nonlinear Hall effect (NLHE) results in a second-harmonic transverse voltage in response to alternating longitudinal current in zero magnetic field and has so far only been observed at low temperatures in bulk materials. Here, the authors observe bulk NLHE at room temperature in the Dirac material BaMnSb₂, which will provide a large photocurrent for applications in THz detection.

Circularly polarized light emitted from OLEDs exhibits opposite handedness depending on the propagation direction of the light. Switching the current flow in the OLED also switches the light handedness.

Under an applied current, chiral antiferromagnets, such as Mn₃Sn, can produce a spin-polarized current. Here, by varying the thickness of a buffering layer, the authors show that this spin-polarized current can drive self-induced switching in polycrystalline Mn₃Sn.

Scanning tunnelling microscopy experiments uncover a primary pair density wave at the reconstructed surface of the kagome metal CsV₃Sb₅, and tip-assisted, atomically precise manipulation of the reconstruction provides control over the emergent quasi-two-dimensional superconductivity.

An orbital polarization effect is proposed to understand chiral-induced spin selectivity.

Weyl semimetals are predicted to exhibit a host of unusual transport properties. NbP, a system predicted to share characteristics of both normal and Weyl semimetals, is now shown to have a very large, non-saturating magnetoresistance.

Two dimensional (2D) material with intriguing physical properties promises advanced electronic and spintronic technologies. Here the authors predict a magnetic photo-galvanic effect (MPGE) in bilayer 2D CrI₃ due to the magnetism-induced asymmetry of the carrier velocity in the band-structure topology.

Band topology of Weyl semimetals is usually predetermined by material parameters and can hardly be manipulated, and their transport properties appear at low temperature. Here, the authors modify the topology via a weak magnetic field and observe a giant anomalous Hall effect at room temperature.

Magnetoresistance of topological semimetal shows unusual electron transport behaviour. Here, Arnold et al. demonstrate detailed Fermi surface topology of Weyl semimetal TaP and show that negative longitudinal magnetoresistance shows up without well-defined Weyl fermions.

Defect engineering in topological materials is a frontier that promises tunable physical properties with rich applications. Here, the authors demonstrate the atomically precise engineering of vacancies in a topological semimetal, which locally tunes the magnetic properties.

Air-stable, non-encapsulated Bi₂O₂Se ultrathin films grown by chemical vapour deposition display high electron mobility and exceptional semiconducting transport properties, making the observation of quantum oscillations possible and suggesting potential applications in electronics.

An ab initio study suggests that a known oxide superconductor, BaBiO₃, can be doped into a topological insulating state. This would simplify topological insulator–superconductor structures for applications.

The half-Heusler GdPtBi is found to show transport and calorimetric signatures of the existence of Weyl fermions under the application of a magnetic field. The half-Heusler alloys form a big family of tunable compounds that may substantially enlarge the number of Weyl semimetals known.

Several recent experimental studies have found disconnected Fermi surface arcs emerging below the Neel temperature in several rare-earth mono-pnictides. While these electronic states have been attributed to a non-collinear antiferromagnetic order, experimental evidence of this has been lacking. Here Huang et al demonstrate the emergence of non-collinear antiferromagnetic order using spin-polarized scanning tunnelling microscopy.

Spectroscopic study on a kagome magnet thin film uncovers the local-moment nature of the magnetism in the presence of topological flat bands, as well as a strong spin- and orbital-selective electronic correlation effect.

Bi₂TeI is identified as a dual topological insulator. It is a weak topological insulator with metallic states at the (010) surfaces and a topological crystalline insulator at the (001) surfaces.

Although novel topological quasiparticles have recently been evidenced, their electrical transport properties remain elusive. Here, the authors report ultra-low resistivity down to 6 nΩcm at 2 K in MoP with a large mean free path, which hints on the exotic properties of triple point fermions.

In situ evaporation of Eu and As onto InAs nanowires results in the mutual exchange of Eu from the shell with In from the core. This solid-state exchange reaction converts wurtzite InAs nanowires into Zintl Eu₃In₂As₄.

Semimetals with the band structure exhibiting Dirac and Weyl crossings can show special electronic and magnetic properties. Here the authors explore the electronic properties of the type-II Weyl semimetals, MoP₂ and WP₂ with robust Weyl points which display very high magnetoresistance and conductivity.

Extreme magnetoresistance (XMR) is the name assigned to the large and non-saturating magnetoresistance that occurs in some metals and semi-metals. In this work, the authors demonstrate the first material, PtSn₄, in which XMR can be switched off by changing the direction of the magnetic field.

Van der Waals heterostructures allow for the integration of several materials with different properties in the one heterostructure. Here, Li et al combine a quantum spin hall insulator, WTe2, with an insulating ferromagnet, Cr2Ge2Te6, in a van der Waals heterostructure, with resulting proximity-induced magnetism in the WTe2 layer leading to an anomalous Hall and Nernst effect.

Recent experiments reported the Kondo effect in 1H/1T dichalcogenide hetero-bilayers. Crippa et al. re-examine this interpretation using ab initio calculations and dynamical mean-field theory demonstrating strong charge transfer sensitive to the interlayer separation, indicative of a doped Mott insulator regime.