Potential magnetic structure in Eu3InAs3 revealed by magnetization and thermodynamic study.

We systematically investigate the magnetization and thermodynamic responses associated with antiferromagnetic (AFM) transitions in single crystals of the magnetic semiconductor Eu3InAs3. The linear thermal expansion measurements around the AFM transition temperatures, TN1 and TN2, indicate an expansion along the a axis and contraction along the b and c axes. The calculated ∆V/V(T) shows a continuous change at TN, indicating a second-order magnetic phase transition.

Highly Efficient Electrode of Dirac Semimetal PtTe for MoS-Based Field Effect Transistors.

Two-dimensional van der Waals (vdW) layered materials not only are an intriguing fundamental scientific research platform but also provide various applications to multifunctional quantum devices in the field-effect transistors (FET) thanks to their excellent physical properties. However, a metal-semiconductor (MS) interface with a large Schottky barrier causes serious problems for unleashing their intrinsic potentials toward the advancements in high-performance devices. Here, we show that exfoliated vdW Dirac semimetallic PtTe can be an excellent electrode for electrons in MoS FETs.

Incommensurate charge super-modulation and hidden dipole order in layered kitaev material α-RuCl.

The magnetism of Kitaev materials has been widely studied, but their charge properties and the coupling to other degrees of freedom are less known. Here we investigate the charge states of α-RuCl, a promising Kitaev quantum spin liquid candidate, in proximity to graphite. We discover that few-layered α-RuCl experiences a clear modulation of charge states, where a Mott-insulator to weak charge-transfer-insulator transition in the 2D limit occurs by means of heterointerfacial polarization.

Chiral kagome superconductivity modulations with residual Fermi arcs.

Superconductivity involving finite-momentum pairing can lead to spatial-gap and pair-density modulations, as well as Bogoliubov Fermi states within the superconducting gap. However, the experimental realization of their intertwined relations has been challenging. Here we detect chiral kagome superconductivity modulations with residual Fermi arcs in KVSb and CsVSb using normal and Josephson scanning tunnelling microscopy down to 30 millikelvin with a resolved electronic energy difference at the microelectronvolt level.

Robust Field-Free Switching Using Large Unconventional Spin-Orbit Torque in an All-Van der Waals Heterostructure.

The emerging all-van der Waals (vdW) magnetic heterostructure provides a new platform to control the magnetization by the electric field beyond the traditional spintronics devices. One promising strategy is using unconventional spin-orbit torque (SOT) exerted by the out-of-plane polarized spin current to enable deterministic magnetization switching and enhance the switching efficiency. However, in all-vdW heterostructures, large unconventional SOT remains elusive and the robustness of the field-free switching against external magnetic field has not been examined, which hinders further applications.

Nonlinear optical signatures of topological Dirac fermion.

Dirac fermion in topological materials exhibits intriguing nonlinear optical responses. However, their direct correlation with the linearly dispersed band remains elusive experimentally. Here, we take topological semimetal ZrSiS as a paradigm, unveiling three unique nonlinear optical signatures of Dirac fermion.

All van der Waals Semiconducting PtSe Field Effect Transistors with Low Contact Resistance Graphite Electrodes.

Contact resistance is a multifaceted challenge faced by the 2D materials community. Large Schottky barrier heights and gap-state pinning are active obstacles that require an integrated approach to achieve the development of high-performance electronic devices based on 2D materials. In this work, we present semiconducting PtSe field effect transistors with all-van-der-Waals electrode and dielectric interfaces.

Evidence for multiferroicity in single-layer CuCrSe.

Multiferroic materials, which simultaneously exhibit ferroelectricity and magnetism, have attracted substantial attention due to their fascinating physical properties and potential technological applications. With the trends towards device miniaturization, there is an increasing demand for the persistence of multiferroicity in single-layer materials at elevated temperatures. Here, we report high-temperature multiferroicity in single-layer CuCrSe, which hosts room-temperature ferroelectricity and 120 K ferromagnetism.

Gold-Template-Assisted Mechanical Exfoliation of Large-Area 2D Layers Enables Efficient and Precise Construction of Moiré Superlattices.

Moiré superlattices, consisting of rotationally aligned 2D atomically thin layers, provide a highly novel platform for the study of correlated quantum phenomena. However, reliable and efficient construction of moiré superlattices is challenging because of difficulties to accurately angle-align small exfoliated 2D layers and the need to shun wet-transfer processes. Here, efficient and precise construction of various moiré superlattices is demonstrated by picking up and stacking large-area 2D mono- or few-layer crystals with predetermined crystal axes, made possible by a gold-template-assisted mechanical exfoliation method.

Dual quantum spin Hall insulator by density-tuned correlations in TaIrTe.

The convergence of topology and correlations represents a highly coveted realm in the pursuit of new quantum states of matter. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order, not possible in quantum Hall and Chern insulator systems. Here we report a new dual QSH insulator within the intrinsic monolayer crystal of TaIrTe, arising from the interplay of its single-particle topology and density-tuned electron correlations.

Observation of Emergent Superconductivity in the Topological Insulator TaPdTe via Pressure Manipulation.

Topological insulators offer significant potential to revolutionize diverse fields driven by nontrivial manifestations of their topological electronic band structures. However, the realization of superior integration between exotic topological states and superconductivity for practical applications remains a challenge, necessitating a profound understanding of intricate mechanisms. Here, we report experimental observations for a novel superconducting phase in the pressurized second-order topological insulator candidate TaPdTe, and the high-pressure phase maintains its original ambient pressure lattice symmetry up to 45 GPa.

Resonant x-ray diffraction measurements in charge ordered kagome superconductors KVSband RbVSb.

We report on (resonant) x-ray diffraction experiments on the normal state properties of kagome-lattice superconductors KVSband RbVSb. We have confirmed previous reports indicating that the charge density wave (CDW) phase is characterized by a doubling of the unit cell in all three crystallographic directions. By monitoring the temperature dependence of Bragg peaks associated with the CDW phase, we ascertained that it develops gradually over several degrees, as opposed to CsVSb, where the CDW peak intensity saturates promptly just below the CDW transition temperature.

Possible quantum-spin-liquid state in van der Waals cluster magnet NbCl.

The cluster magnet NbClconsists of Nbtrimmers that form an emergent= 1/2 two-dimensional triangular layers, which are bonded by weak van der Waals interactions. Recent studies show that its room-temperature electronic state can be well described as a single-band Mott insulator. However, the magnetic ground state is non-magnetic due to a structural transition below about 100 K.

A robust and tunable Luttinger liquid in correlated edge of transition-metal second-order topological insulator TaPdTe.

The interplay between topology and interaction always plays an important role in condensed matter physics and induces many exotic quantum phases, while rare transition metal layered material (TMLM) has been proved to possess both. Here we report a TMLM TaPdTe has the two-dimensional second-order topology (also a quadrupole topological insulator) with correlated edge states - Luttinger liquid. It is ascribed to the unconventional nature of the mismatch between charge- and atomic- centers induced by a remarkable double-band inversion.

Emergence of Weyl fermions by ferrimagnetism in a noncentrosymmetric magnetic Weyl semimetal.

Condensed matter physics has often provided a platform for investigating the interplay between particles and fields in cases that have not been observed in high-energy physics. Here, using angle-resolved photoemission spectroscopy, we provide an example of this by visualizing the electronic structure of a noncentrosymmetric magnetic Weyl semimetal candidate NdAlSi in both the paramagnetic and ferrimagnetic states. We observe surface Fermi arcs and bulk Weyl fermion dispersion as well as the emergence of new Weyl fermions in the ferrimagnetic state.

Room temperature field-free switching of perpendicular magnetization through spin-orbit torque originating from low-symmetry type II Weyl semimetal.

Spin-orbit torque (SOT) is a promising strategy to deterministically switch the perpendicular magnetization, but usually requires an in-plane magnetic field for breaking the mirror symmetry, which is not suitable for most advanced industrial applications. Van der Waals (vdW) materials with low crystalline symmetry and topological band structures, e.g.

Extrinsic Nonlinear Kerr Rotation in Topological Materials under a Magnetic Field.

Topological properties in quantum materials are often governed by symmetry and tuned by crystal structure and external fields, and hence, symmetry-sensitive nonlinear optical measurements in a magnetic field are a valuable probe. Here, we report nonlinear magneto-optical second harmonic generation (SHG) studies of nonmagnetic topological materials including bilayer WTe, monolayer WSe, and bulk TaAs. The polarization-resolved patterns of optical SHG under a magnetic field show nonlinear Kerr rotation in these time-reversal symmetric materials.

Improved figure of merit (z) at low temperatures for superior thermoelectric cooling in Mg(Bi,Sb).

The low-temperature thermoelectric performance of Bi-rich n-type Mg(Bi,Sb) was limited by the electron transport scattering at grain boundaries, while removing grain boundaries and bulk crystal growth of Mg-based Zintl phases are challenging due to the volatilities of elemental reactants and their severe corrosions to crucibles at elevated temperatures. Herein, for the first time, we reported a facile growth of coarse-grained MgBiSb crystals with an average grain size of ~800 μm, leading to a high carrier mobility of 210 cm · V · s and a high z of 2.9 × 10K at 300 K.

Electrical detection of spin pumping in van der Waals ferromagnetic CrGeTe with low magnetic damping.

The discovery of magnetic order in atomically-thin van der Waals materials has strengthened the alliance between spintronics and two-dimensional materials. An important use of magnetic two-dimensional materials in spintronic devices, which has not yet been demonstrated, would be for coherent spin injection via the spin-pumping effect. Here, we report spin pumping from CrGeTe into Pt or W and detection of the spin current by inverse spin Hall effect.

Controllable dimensionality conversion between 1D and 2D CrCl magnetic nanostructures.

The fabrication of one-dimensional (1D) magnetic systems on solid surfaces, although of high fundamental interest, has yet to be achieved for a crossover between two-dimensional (2D) magnetic layers and their associated 1D spin chain systems. In this study, we report the fabrication of 1D single-unit-cell-width CrCl atomic wires and their stacked few-wire arrays on the surface of a van der Waals (vdW) superconductor NbSe. Scanning tunneling microscopy/spectroscopy and first-principles calculations jointly revealed that the single wire shows an antiferromagnetic large-bandgap semiconducting state in an unexplored structure different from the well-known 2D CrCl phase.

Strong magnetic anisotropy in PrRuGaand PrCoAlsingle crystals.

Single crystals ofRuGaandCoAl(= La and Pr) were grown using a Ga/Al self-flux method. An orthorhombic CaCoAl-type structure with space group(No.55) of them was identified by x-ray diffraction.

Testing electron-phonon coupling for the superconductivity in kagome metal CsVSb.

In crystalline materials, electron-phonon coupling (EPC) is a ubiquitous many-body interaction that drives conventional Bardeen-Cooper-Schrieffer superconductivity. Recently, in a new kagome metal CsVSb, superconductivity that possibly intertwines with time-reversal and spatial symmetry-breaking orders is observed. Density functional theory calculations predicted weak EPC strength, λ, supporting an unconventional pairing mechanism in CsVSb.