Skin Effect of Nonlinear Optical Responses in Antiferromagnets.

Nonlinear optics plays important roles in the research of fundamental physics and the applications of high-performance optoelectronic devices. The bulk nonlinear optical responses arise from the uniform light absorption in noncentrosymmetric crystals, and hence are usually considered to be the collective phenomena of all atoms. Here we show, in contrast to this common expectation, the nonlinear optical responses in antiferromagnets can be selectively accumulated near the surfaces, representing a skin effect.

Tuning d-Orbital Electronic Structure via Au-Intercalated Two-Dimensional FeGeTe to Increase Surface Plasmon Activity.

While extensive research has been dedicated to plasmon tuning within non-noble metals, prior investigations primarily concentrated on markedly augmenting the inherently low concentration of free carriers in materials with minimal consideration given to the influence of electron orbitals on surface plasmons. Here, we achieve successful intercalation of Au atoms into the layered structure of FeGeTe (FGT), thereby exerting control over the orbital electronic states or structure of FGT. This intervention not only amplifies the charge density and electron mobility but also mitigates the loss associated with interband transitions, resulting in increased two-dimensional FGT surface plasmon activity.

Enhanced Superconductivity and Critical Current Density Due to the Interaction of InSe Bonded Layer in (InSe)NbSe.

Superconductivity was discovered in (InSe)NbSe. The materials are crystallized in a unique layered structure where bonded InSe layers are intercalated into the van der Waals gaps of 2H-phase NbSe. The (InSe)NbSe superconductor exhibits a superconducting transition at 11.

A mixed-dimensional quasi-1D BiSeI nanowire-2D GaSe nanosheet p-n heterojunction for fast response optoelectronic devices.

Due to the unique combination configuration and the formation of a built-in electric field, mixed-dimensional heterojunctions present fruitful possibilities for improving the optoelectronic performances of low-dimensional optoelectronic devices. However, the response times of most photodetectors built from mixed-dimensional heterojunctions are within the millisecond range, limiting their applications in fast response optoelectronic devices. Herein, a mixed-dimensional BiSeI/GaSe van der Waals heterostructure is designed, which exhibits visible light detection ability and competitive photoresponsivity of 750 A W and specific detectivity of 2.

Defect Emission and Its Dipole Orientation in Layered Ternary Znln S Semiconductor.

Defect engineering is promising to tailor the physical properties of 2D semiconductors for function-oriented electronics and optoelectronics. Compared with the extensively studied 2D binary materials, the origin of defects and their influence on physical properties of 2D ternary semiconductors are not clarified. Here, the effect of defects on the electronic structure and optical properties of few-layer hexagonal Znln S is thoroughly studied via versatile spectroscopic tools in combination with theoretical calculations.

Near-Neighbor Electron Orbital Coupling Effect of Single-Atomic-Layer Au Cluster Intercalated Bilayer 2H-TaS for Surface Enhanced Raman Scattering Sensing.

It is difficult to perfectly analyze the enhancement mechanism of two-dimensional (2D) materials and their combination with precious metals as surface enhanced Raman scattering (SERS) substrates using chemical enhancement mechanisms. Here, we propose a new mentality based on the coupling effect of neighboring electron orbitals to elucidate the electromagnetic field enhancement mechanism of single-atom-layer Au clusters embedded in double-layer 2H-TaS for SRES sensing. The insertion of Au atoms into the 2H-TaS interlayer was verified by XRD, AFM, and HRTEM, and a SERS signal enhancement of 2 orders of magnitude was obtained compared to the pure 2H-TaS.

Extending Plasmonic Enhancement Limit with Blocked Electron Tunneling by Monolayer Hexagonal Boron Nitride.

Fabricating ultrasmall nanogaps for significant electromagnetic enhancement is a long-standing goal of surface-enhanced Raman scattering (SERS) research. However, such electromagnetic enhancement is limited by quantum plasmonics as the gap size decreases below the quantum tunneling regime. Here, hexagonal boron nitride (h-BN) is sandwiched as a gap spacer in a nanoparticle-on-mirror (NPoM) structure, effectively blocking electron tunneling.

Poly(vinyl alcohol)-Assisted Exfoliation of van der Waals Materials.

We report a highly efficient and easily transferable poly(vinyl alcohol) (PVA)-assisted exfoliation method, which allows one to obtain van der Waals materials on large scales, e.g., centimeter-scale graphite flakes and hundred-micrometer-scale several layers of ZnInS and BN.

A tellurium short-wave infrared photodetector with fast response and high specific detectivity.

Two-dimensional (2D) elementary tellurium (Te) has attracted intensive attention due to its potential applications in short-wave infrared photodetector devices. Here, we report hydrothermally synthesized 2D Te nanoflakes for short-wave infrared photodetectors with high performance. A Te-based photodetector exhibits a peak responsivity of 51.

Enhanced magnetism and persistent insulating state in Mn doped SrIrO.

The influences of Mn substitution at the Ir site of SrIrOare investigated via a comprehensive study of the variation of structural parameters, the transport and magnetic properties of the SrIrMnOsamples. The incorporation of Mn leads to an increase of the in-plane Ir-O-Ir bond angle, while it is not sufficient to drive the Mott-insulating state to a metallic state. Interestingly, we find a coexistence of Ir-O-Irsuper-exchange interaction and Mn-O-Mndouble exchange interaction in⩾ 0.

Ultrasensitive, Ultrafast, and Gate-Tunable Two-Dimensional Photodetectors in Ternary Rhombohedral ZnInS for Optical Neural Networks.

The demand for high-performance semiconductors in electronics and optoelectronics has prompted the expansion of low-dimensional materials research to ternary compounds. However, photodetectors based on 2D ternary materials usually suffer from large dark currents and slow response, which means increased power consumption and reduced performance. Here we report a systematic study of the optoelectronic properties of well-characterized rhombohedral ZnInS (R-ZIS) nanosheets which exhibit an extremely low dark current (7 pA at 5 V bias).

Estimating quantum steering and Bell nonlocality through quantum entanglement in two-photon systems.

Quantum entanglement, quantum steering and Bell nonlocality, as significant quantum resources in the field of quantum information science, can achieve variously valuable quantum information tasks. Among of them, quantum entanglement and Bell nonlocality are the weakest and strongest nonlocal correlations, respectively. One can capture the quantum steering and Bell nonlocality via violating steering inequality and Bell inequality, respectively.

Global phase diagram of Coulomb-interacting anisotropic Weyl semimetal with disorder.

Taking into account the interplay between the disorder and Coulomb interaction, the phase diagram of three-dimensional anisotropic Weyl semimetal is studied by renormalization group (RG) theory. Weak disorder is irrelevant in anisotropic Weyl semimetal, while the disorder becomes relevant and drives a quantum phase transition (QPT) from semimetal to compressible diffusive metal (CDM) phases if the disorder strength is larger than a critical value. The long-range Coulomb interaction is irrelevant in clean anisotropic Weyl semimetal.

Record-High Superconductivity in Niobium-Titanium Alloy.

The extraordinary superconductivity has been observed in a pressurized commercial niobium-titanium alloy. Its zero-resistance superconductivity persists from ambient pressure to the pressure as high as 261.7 GPa, a record-high pressure up to which a known superconducting state can continuously survive.

Opposite pressure effects in the orbitally-induced Peierls phase transition systems CuIrS and MgTiO.

The iso-spinel structural systems CuIrS and MgTiO exhibit phase transitions of a similar nature at ∼230 K and ∼260 K respectively, which are explained as an orbitally-induced Peierls phase transition. However, in this work, we uncover that the applied pressure has opposite pressure effects on the phase transitions in CuIrS and MgTiO. As the pressure increases, the phase transition temperature (T) for CuIrS increases while that for MgTiO decreases.

Drive the Dirac electrons into Cooper pairs in SrBiSe.

Topological superconductors are a very interesting and frontier topic in condensed matter physics. Despite the tremendous efforts in exploring topological superconductivity, its presence is however still under heavy debate. The Dirac electrons have been proven to exist on the surface of a topological insulator.

Anisotropic magnetic coupling with a two-dimensional characteristic in noncentrosymmetric CrGe.

In this work, we successfully synthesize the single crystal CrGe. The magnetism of the noncentrosymmetric CrGe with itinerant ferromagnetic ground state is thoroughly investigated on the single crystal. Based on the variation measurements including the angular rotation, temperature, and magnetic field dependence of magnetization, we find that this material exhibits strong magnetic anisotropy along the c-axis.

De Hass-van Alphen and magnetoresistance reveal predominantly single-band transport behavior in PdTe2.

Research on two-dimensional transition metal dichalcogenides (TMDs) has grown rapidly over the past several years, from fundamental studies to the development of next generation technologies. Recently, it has been reported that the MX2-type PdTe2 exhibits superconductivity with topological surface state, making this compound a promising candidate for investigating possible topological superconductivity. However, due to the multi-band feature of most of TMDs, the investigating of magnetoresistance and quantum oscillations of these TMDs proves to be quite complicated.

Critical phenomenon of the near room temperature skyrmion material FeGe.

The cubic B20 compound FeGe, which exhibits a near room temperature skyrmion phase, is of great importance not only for fundamental physics such as nonlinear magnetic ordering and solitons but also for future application of skyrmion states in spintronics. In this work, the critical behavior of the cubic FeGe is investigated by means of bulk dc-magnetization. We obtain the critical exponents (β = 0.

Superconductivity with Topological Surface State in SrxBi₂Se₃.

By intercalation of alkaline earth metal Sr in Bi2Se3, superconductivity with large shielding volume fraction (∼91.5% at 0.5 K) has been achieved in Sr0.

Superconducting fiber with transition temperature up to 7.43 K in Nb2PdxS5-δ (0.6 < x <1).

Wiring systems powered by highly efficient superconductors have long been a dream of scientists, but researchers have faced practical challenges such as finding flexible materials. Here we report superconductivity in Nb2PdxS5-δ fibers with transition temperature up to 7.43 K, which have typical diameters of 0.