Synthesis of a semimetallic Weyl ferromagnet with point Fermi surface.

Quantum materials governed by emergent topological fermions have become a cornerstone of physics. Dirac fermions in graphene form the basis for moiré quantum matter and Dirac fermions in magnetic topological insulators enabled the discovery of the quantum anomalous Hall (QAH) effect. By contrast, there are few materials whose electromagnetic response is dominated by emergent Weyl fermions.

Charge Density Modulation and the Luttinger Liquid State in MoSe Mirror Twin Boundaries.

A mirror twin-domain boundary (MTB) in monolayer MoSe represents a (quasi) one-dimensional metallic system. Its electronic properties, particularly the low-energy excitations in the so-called 4|4P-type MTB, have drawn considerable research attention. Reports of quantum well states, charge density waves, and the Tomonaga-Luttinger liquid (TLL) have all been made.

The effect of DMPO on the formation of hydroxyl radicals on the rutile TiO(110) surface.

Unraveling the formation mechanism of hydroxyl radicals (OH˙) is one of the outstanding issues in photocatalytic reactions, where 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is widely utilized as a trapping agent to detect OH˙ radicals in experiments. In this study, we carry out density functional theory calculations to reveal the origin and formation process of OH˙ radicals by investigating the interaction of water with DMPO on a rutile TiO(110) surface. Our results clearly show that the OH˙ radicals trapped by DMPO stem from water upon illumination.

Topological Quantum States in Magnetic Oxides.

The realization of topological quantum states in devices is an important subject. According to whether or not the time-reversal symmetry is broken, topological materials can be classified into magnetic and nonmagnetic ones. In particular, magnetic topological materials are of importance, in which the coexistence of nontrivial band topology and magnetic orders gives exotic spintronics-related applications.

Quantum Confined Tomonaga-Luttinger Liquid in MoSe Nanowires Converted from an Epitaxial MoSe Monolayer.

Confining interacting particles in one-dimension (1D) changes the electronic behavior of the system fundamentally, which has been studied extensively in the past. Examples of 1D metallic systems include carbon nanotubes, quasi-1D organic conductors, metal chains, and domain boundary defects in monolayer thick transition-metal dichalcogenides such as MoSe. Here single and bundles of MoSe nanowires were fabricated through annealing a MoSe monolayer grown by molecular-beam epitaxy on graphene.

Recipe for Dirac Phonon States with a Quantized Valley Berry Phase in Two-Dimensional Hexagonal Lattices.

The topological quantum states in two-dimensional (2D) materials are fascinating subjects of research, which usually highlight electron-related systems. In this work, we present a recipe that leads to Dirac phonon states with a quantized valley Berry phase in 2D hexagonal lattices by first-principles calculations. We show that candidates possessing the 3-fold rotational symmetry at the corners of the hexagonal Brillouin zone host valley Dirac phonons, which are guaranteed to remain intact with respect to perturbations.

Oxidation-Induced Topological Phase Transition in Monolayer 1T'-WTe.

Monolayer (ML) tungsten ditelluride (WTe) is a well-known quantum spin Hall (QSH) insulator with topologically protected gapless edge states, thus promising dissipationless electronic devices. However, experimental findings exhibit the fast oxidation of ML WTe in ambient conditions. To reveal the changes of topological properties of WTe arising from oxidation, we systematically study the surface oxidation reaction of ML 1T'-WTe using first-principles calculations.

The prediction of a family group of two-dimensional node-line semimetals.

Using first-principles calculations, we predict a family group of two-dimensional semimetals MX (M = Pd, Pt; X = S, Se, Te), which has a zig-zag type mono-layer structure in the Pmma (no. 41) layer group. Band structure analysis reveals that node-line features are caused by band inversion and the inversion exists even in the absence of spin-orbital-coupling.

Theoretical study of HgCr2Se3.5Te0.5: a doping-site-dependent semimetal.

Weyl semimetals have recently attracted enormous attention due to their unusual features. So far, this novel state has been predicted theoretically and confirmed experimentally in several materials, such as HgTe, LaPtBi, Y2Ir2O7, TaAs, TaP, NbAs, NbP and HgCr2Se4. Doping plays an important role in the research of condensed-matter materials.