Proximity induced charge density wave in a graphene/1T-TaS heterostructure.

The proximity-effect, whereby materials in contact appropriate each other's electronic-properties, is widely used to induce correlated states, such as superconductivity or magnetism, at heterostructure interfaces. Thus far however, demonstrating the existence of proximity-induced charge-density-waves (PI-CDW) proved challenging. This is due to competing effects, such as screening or co-tunneling into the parent material, that obscured its presence.

Dual Dirac Nodal Line in Nearly Freestanding Electronic Structure of β-Sn Monolayer.

Two-dimensional topological insulators (2D TIs) have distinct electronic properties that make them attractive for various applications, especially in spintronics. The conductive edge states in 2D TIs are protected from disorder and perturbations and are spin-polarized, which restrict current flow to a single spin orientation. In contrast, topological nodal line semimetals (TNLSM) are distinct from TIs because of the presence of a 1D ring of degeneracy formed from two bands that cross each other along a line in the Brillouin zone.

Giant X-Ray Circular Dichroism in a Time-Reversal Invariant Antiferromagnet.

X-ray circular dichroism, arising from the contrast in X-ray absorption between opposite photon helicities, serves as a spectroscopic tool to measure the magnetization of ferromagnetic materials and identify the handedness of chiral crystals. Antiferromagnets with crystallographic chirality typically lack X-ray magnetic circular dichroism because of time-reversal symmetry, yet exhibit weak X-ray natural circular dichroism. Here, the observation of giant natural circular dichroism in the Ni L-edge X-ray absorption of NiTeO is reported, a polar and chiral antiferromagnet with effective time-reversal symmetry.

Two-gap topological superconductor LaB with high = 30 K.

Since two gap superconductivity was discovered in MgB, research on multigap superconductors has attracted increasing attention because of its intriguing fundamental physics. In MgB, the Mg atom donates two electrons to the borophene layer, resulting in a stronger gap from the σ band and a weaker gap from the π bond. First-principles calculations demonstrate that the two gap anisotropic superconductivity strongly enhances the transition temperature of MgB in comparison with that given by the isotropic model.

Magnetoelastic and Magnetoelectric Coupling in Two-Dimensional Nitride MXenes: A Density Functional Theory Study.

Two-dimensional multiferroic (2D) materials have garnered significant attention due to their potential in high-density, low-power multistate storage and spintronics applications. MXenes, a class of 2D transition metal carbides and nitrides, were first discovered in 2011, and have become the focus of research in various disciplines. Our study, utilizing first-principles calculations, examines the lattice structures, and electronic and magnetic properties of nitride MXenes with intrinsic band gaps, including VNF, VNO, CrNF, MoNO, MoNF, and MnNO.

Correction: Magnetoconductance modulations due to interlayer tunneling in radial superlattices.

Correction for 'Magnetoconductance modulations due to interlayer tunneling in radial superlattices' by Yu-Jie Zhong , , 2022, , 168-173, https://doi.org/10.1039/D1NH00449B.

Formation Mechanism and Bandgap Reduction of GaN-ZnO Solid-Solution Thin Films Fabricated by Nanolamination of Atomic Layer Deposition.

Nanolamination of GaN and ZnO layers by atomic layer deposition (ALD) is employed to fabricate GaN-ZnO homogenous solid-solution thin films because it offers more precise control of the stoichiometry. By varying the ALD cycle ratios of GaN:ZnO from 5:10 to 10:5, the (GaN) (ZnO) films with 0.39 ≦ x ≦ 0.

Dirac Nodal Line in Hourglass Semimetal NbSiTe.

Glide-mirror symmetry in nonsymmorphic crystals can foster the emergence of novel hourglass nodal loop states. Here, we present spectroscopic signatures from angle-resolved photoemission of a predicted topological hourglass semimetal phase in NbSiTe. Linear band crossings are observed at the zone boundary of NbSiTe, which could be the origin of the nontrivial Berry phase and are consistent with a predicted glide quantum spin Hall effect; such linear band crossings connect to form a nodal loop.

Electric control of valley polarization in monolayer WSe using a van der Waals magnet.

Electrical manipulation of the valley degree of freedom in transition metal dichalcogenides is central to developing valleytronics. Towards this end, ferromagnetic contacts, such as Ga(Mn)As and permalloy, have been exploited to inject spin-polarized carriers into transition metal dichalcogenides to realize valley-dependent polarization. However, these materials require either a high external magnetic field or complicated epitaxial growth steps, limiting their practical applications.

Modulation Doping Enables Ultrahigh Power Factor and Thermoelectric ZT in n-Type Bi Te Se.

Bismuth telluride-based thermoelectric (TE) materials are historically recognized as the best p-type (ZT = 1.8) TE materials at room temperature. However, the poor performance of n-type (ZT≈1.

Threefold Fermions, Weyl Points, and Superconductivity in the Mirror Symmetry Lacking Semiconductor TlCdTe.

The topological phase transition and exotic quasiparticles in materials have attracted much attention because of their potential in spintronics and mimic of elementary particles. Especially, great research interest has been paid to search for the Weyl fermions in solid-state physics. By using first-principles calculations, we predict that the multinary semiconductor alloy TlCd2Te4 exhibits threefold fermions and nodal-line fermions, which are protected by the S4 improper rotational symmetry.

Enormous Berry-Curvature-Based Anomalous Hall Effect in Topological Insulator (Bi,Sb)Te on Ferrimagnetic Europium Iron Garnet beyond 400 K.

To realize the quantum anomalous Hall effect (QAHE) at elevated temperatures, the approach of magnetic proximity effect (MPE) was adopted to break the time-reversal symmetry in the topological insulator (BiSb)Te (BST) based heterostructures with a ferrimagnetic insulator europium iron garnet (EuIG) of perpendicular magnetic anisotropy. Here we demonstrate large anomalous Hall resistance () exceeding 8 Ω ( of 3.2 μΩ·cm) at 300 K and sustaining to 400 K in 35 BST/EuIG samples, surpassing the past record of 0.

Magnetoconductance modulations due to interlayer tunneling in radial superlattices.

Radial superlattices are nanostructured materials obtained by rolling up thin solid films into spiral-like tubular structures. The formation of these "high-order" superlattices from two-dimensional crystals or ultrathin films is expected to result in a transition of transport characteristics from two-dimensional to one-dimensional. Here, we show that a transport hallmark of radial superlattices is the appearance of magnetoconductance modulations in the presence of externally applied axial magnetic fields.

Topological Phase and Quantum Anomalous Hall Effect in Ferromagnetic Transition-Metal Dichalcogenides Monolayer 1T-VSe2.

Magnetic two-dimensional (2D) van der Waals materials have attracted tremendous attention because of their high potential in spintronics. In particular, the quantum anomalous Hall (QAH) effect in magnetic 2D layers shows a very promising prospect for hosting Majorana zero modes at the topologically protected edge states in proximity to superconductors. However, the QAH effect has not yet been experimentally realized in monolayer systems to date.

Topological Proximity-Induced Dirac Fermion in Two-Dimensional Antimonene.

Antimonene is a promising two-dimensional (2D) material that is calculated to have a significant fundamental bandgap usable for advanced applications such as field-effect transistors, photoelectric devices, and the quantum-spin Hall (QSH) state. Herein, we demonstrate a phenomenon termed topological proximity effect, which occurs between a 2D material and a three-dimensional (3D) topological insulator (TI). We provide strong evidence derived from hydrogen etching on SbTe that large-area and well-ordered antimonene presents a 2D topological state.

Optomechanical switching of adsorption configurations of polar organic molecules by UV radiation pressure.

Using photoemission spectroscopy (PES), we have systematically investigated the behavior of polar organic molecule, chloroaluminum phthalocyanine (ClAlPc), adsorbed in the Cl-down configuration on the Ag(111) substrate at low temperature - 195 °C under UV irradiation with a range of different photon fluxes. Judging from the evolution of photoemission spectral line shapes of molecular energy states, we discovered that the Cl atoms are so robustly anchored at Ag(111) that the impinging photons cannot flip the ClAlPc molecules, but instead they crouch them down due to radiation pressure; we observe that the phthalocyanine (Pc) lobes bend down to interact with Ag atoms on the substrate and induce charge transfer from them. As photon flux is increased, radiation pressure on the Pc plane initiates tunneling of the Cl atom through the molecular plane to turn the adsorption configuration of ClAlPc from Cl-down to an upheld Cl-up configuration, elucidating an optomechanical way of manipulating the dipole direction of polar molecules.

Reduction of dopant ions and enhancement of magnetic properties by UV irradiation in Ce-doped TiO.

We report the experimental observation of and theoretical explanation for the reduction of dopant ions and enhancement of magnetic properties in Ce-doped TiO diluted magnetic semiconductors from UV-light irradiation. Substantial increase in Ce concentration and creation of oxygen vacancy defects in the sample due to UV-light irradiation was observed by X-ray and optical methods. Magnetic measurements demonstrate a combination of paramagnetism and ferromagnetism up to room temperatures in all samples.

A first-principles study of rare earth quaternary Heusler compounds: RXVZ (R = Yb, Lu; X = Fe, Co, Ni; Z = Al, Si).

Rare earth equiatomic quaternary Heusler (EQH) compounds with chemical formula RXVZ (R = Yb, Lu; X = Fe, Co, Ni; Z = Al, Si) have recently attracted much attention since these materials are easily prepared and they also provide interesting properties for future spintronic applications. In this work, rare Earth-based EQH compounds in three types of structures are theoretically investigated through first-principles calculations based on density functional theory. We find that most of the studied rare Earth EQH compounds exhibit magnetic ground states including ferro-, antiferro-, and ferri-magnetic phases.

Topological Phase and Strong Correlation in Rare-Earth Hexaborides XB (X = La, Ce, Pr, Nd, Pm, Sm, Eu).

The rare-earth hexaboride SmB, known as the topological Kondo insulator, has attracted tremendous attention in recent years. It was revealed that the topological phase of SmB is insensitive to the value of on-site Coulomb interactions (Hubbard U), indicating that the topological phase in SmB is robust against strong correlations. On the contrary, the isostructural YbB displays a sensitivity to the Hubbard U value.

Green Treatment of Phosphate from Wastewater Using a Porous Bio-Templated Graphene Oxide/MgMn-Layered Double Hydroxide Composite.

Excessive phosphorus in water is the primary culprit for eutrophication, which causes approximately $2.2 billion annual economic loss in the United States. This study demonstrates a phosphate-selective sustainable method by adopting Garcinia subelliptica leaves as a natural bio-template, where MgMn-layered double hydroxide (MgMn-LDH) and graphene oxide (GO) can be grown in situ to obtain L-GO/MgMn-LDH.

Orbital ordering and magnetism in layered Perovskite Ruthenate SrRuO.

Local density approximation plus on-site Coulomb interaction U electronic structure calculations reveal that layered perovskite oxide SrRuO exhibits the ferromagnetic (FM) half-metallic ground state, which is nearly degenerate with the antiferromagnetic (AFM) phase with a slightly higher total energy. The nearly degenerate FM/AFM total energies provide a reasonable explanation for the experimentally observed spin-fluctuation. In addition, a dumbbell-shape 4d - t recombined d - d orbital ordering on the Ru sublattice is obtained owing to the on-site Coulomb interaction U associated with the elongated RuO octahedron local structure.

Enhancement of catalytic activity by UV-light irradiation in CeO nanocrystals.

Ultraviolet (UV) light irradiation on CeO nanocrystals catalysts has been observed to largely increase the material's catalytic activity and reactive surface area. As revealed by x-ray absorption near edge structure (XANES) analysis, the concentration of subvalent Ce ions in the irradiated ceria samples progressively increases with the UV-light exposure time. The increase of Ce concentration as a result of UV irradiation was also confirmed by the UV-vis diffuse reflectance and photoluminescence spectra that indicate substantially increased concentration of oxygen vacancy defects in irradiated samples.

Defect engineering by synchrotron radiation X-rays in CeO nanocrystals.

This work reports an unconventional defect engineering approach using synchrotron-radiation-based X-rays on ceria nanocrystal catalysts of particle sizes 4.4-10.6 nm.