The valley-polarized quantum anomalous Hall effect (VQAHE) attracts intensive interest since it uniquely combines valleytronics and spintronics with nontrivial band topology. Here, based on first-principles calculations Wannier-function-based tight-binding (WFTB) model, we reveal that valley-based effects especially the VQAHE induced by external magnetic fields can occur in two-dimensional (2D) ferromagnetic van der Waals heterostructures (vdWHs). results show considerable valley-splitting...

Thermoelectric conversion technology is increasingly important for sustainable energy, particularly in transforming waste heat into electricity. In this study, we explore the thermoelectric properties of three novel two-dimensional materials, monolayer $R\text{TeCl}$ (with $R=\text{La},\text{Pr},\text{Nd}$), using density-functional theory and semiclassical Boltzmann transport theory. These materials are stable can be easily exfoliated from bulk structures due to their low cleavage energy....

Investigations into topological materials typically emphasize either electronic or phononic properties in isolation, often disregarding their coexistence, which could restrict the full realization of practical applications. Here, we investigate HOD-graphene, an emergent macroporous carbon material featuring a unique configuration hexagonal, octagonal, and dodecagonal rings. This distinctive structure imparts exceptional mechanical to material. Using combination first-principles calculations...

Here, based on first-principles calculations and topological analysis, we show that the spin-polarized phase is present in a van der Waals (vdW) heterostructure WSe2/CrI3. We reveal magnetism induced by proximity effects breaks time-reversal symmetry (TRS) thus induces gapped edge states, exhibiting TRS-breaking quantum spin Hall (QSH) effect. By applying stress field, WSe2/CrI3 manifests enhanced polarization, Rashba splitting, tunable bandgap. The QSH effect observed exhibits remarkable...

Bioconversion of elemental mercury (Hg0) into immobile, nontoxic, and less bioavailable species is vital environmental significance. Here, we investigated bioconversion Hg0 in a sulfate-reducing membrane biofilm reactor (MBfR). The MBfR achieved effective removal by sulfate bioreduction. 16 S rDNA sequencing metagenomic revealed that diverse groups mercury-oxidizing/sulfate-reducing bacteria (Desulfobulbus, Desulfuromonas, Desulfomicrobium, etc.) utilized as the initial electron donor...

Realizing stable two-dimensional (2D) Dirac points against spin-orbit coupling (SOC) has attracted much attention because it provides a platform to study the unique transport properties. In previous work, Young and Kane [Phys. Rev. Lett. 115, 126803 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.126803 proposed 2D with SOC, in which Berry curvature edge states vanish due coexistence of inversion time-reversal symmetries. Herein, using tight-binding model k·p effective Hamiltonian, we present...

Different from spin-$\frac{1}{2}$ Weyl points which are robust due to the protection of topology, unconventional chiral quasiparticles usually require extra crystalline symmetries for their existence, indicating that such sensitive perturbation. Herein, we present spin-1 can transform into quadratic phonons depending on symmetry variation. Specifically, nodes arisen three-dimensional (3D) irreducible representations (IRs) point groups, $O$(432) or $T$(23), verified split if breaking...

Two-dimensional (2D) boron nitride (BN) is a promising candidate for aerospace materials due to its excellent mechanical and thermal stability properties. However, unusually prominent band gap limits application prospects. In this work, we report gapless monolayer BN, t-BN, which has four anisotropic Dirac cones in the first Brillouin zone exactly at Fermi level. To further confirm semimetallic character, nontrivial topological properties are proven through topologically protected edge...

Quantum oscillation measurements reveal that in magnetic Weyl semimetals NdAlSi and CeAlSi${}_{0.8}$Ge${}_{0.2}$, the areas of extremal orbits on Fermi surfaces change remarkably with varying temperature; such changes depend local spin configurations magnetic-field directions. The temperature dependence is demonstrated to be a result exchange coupling between localized 4$f$ electrons itinerant 5$d$ electrons.

The exploration of carbon phases with intact massless Dirac fermions in the presence defects is critical for practical applications to nanoelectronics. Here, we identify by first-principles calculations that cones can exist graphene stacking fault (SF) induced periodic line defects. These structures are width (n)-dependent nanoribbon and thus termed as (SF)n-graphene. electronic properties reveal semimetallic features occur (SF)n-graphene n = 3m + 1, where m a positive integer, then lead...

The electronic properties fluctuate with the distinct carbon phases, spanning from semiconductors to nodal line semimetals, contingent upon whether lattice is simple or compound.

Toluene biodegradation from synthetic waste gas by aerobic denitrification using nitrate as an electron acceptor in a biotrickling filter (BTF) was investigated. removal efficiency achieved 92.3% 105 days of operation. Pseudomonas, Paracoccus, Flavobacterium, SM1A02, Acinetobacter, Blastocatella, Moheibacter, Chlamydiales, Rhodobacter, and Ottowia were dominant toluene-degrading genus. Bradyrhizobium, Comamonas, Cupriavidus, Pseuoxanthomonas, Ralstonia simultaneously had the ability to...

Recently, two-dimensional (2D) ternary monolayer MSi2N4 (M = Mo, W) was synthesized by chemical vapor deposition. However, has an indirect bandgap, which seriously hinders its application in optoelectronic devices. Herein, we propose two MSi2N4/InS van der Waals heterojunctions (vdWHs) possessing type-II band alignments first-principles. Our results indicate that these vdWHs achieve indirect-to-direct bandgap transition and exhibit fascinating optical absorption spectra the range of visible...

The exploration of novel two-dimensional semimetallic materials is always an attractive topic. We propose a series silicon carbides with tetragonal lattice. band structure carbon rings and exhibits Dirac cones. Interestingly, the cone SiC originates from "ring coupling" mechanism. This mechanism refers to mutual coupling between four atoms in C ring, same Si ring. Additionally, applicable other group IV binary compounds such as monolayer GeC SnC. work provides reliable evidence for argument...

The grain boundaries (GBs) composed of pentagons and octagons (558 GBs) have been demonstrated to induce attractive transport properties such as Van Hove singularity (VHS) quasi-one-dimensional metallic wires. Here, we propose a monolayer carbon allotrope which is formed from the introduction periodic 558 GBs decorate intact graphene, termed PHO-graphene. calculated electronic indicate that PHO-graphene not only inherits previously superior characteristics wires, but also possesses two...

Unconventional quasiparticles of a twofold band degeneracy with $|C|=4$, named as charge-four Weyl point (CFWP), have been revealed in bosonic and artificial systems, while it is challenging fermionic systems because nonnegligible spin-orbit coupling. Herein, we propose carbon allotrope, termed cP-C24, an ideal platform to realize CFWP the nonrelativistic limit. Besides one ($C=+4$), there are also eight type-I points ($C=+1$) twelve type-II nodes ($C=\ensuremath{-}1$), making topological...

Hourglass-type Weyl fermions with the maximally topological charge of $|C|=3$, namely hourglass-type charge-three (CTWFs), have seldom been reported due to nonnegligible spin-orbit coupling effect and Pauli exclusion principles. Here, based on symmetry arguments low-energy effective $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ model, we confirm that two chiral space groups (SGs), i.e., SG $\mathrm{P}{6}_{3}$ (No. 173) $\mathrm{P}{6}_{3}22$ 182), can host ideal CTWFs in...

The realization of the single-pair fermions in electronic systems remains challenging topology physics, especially for with larger chiral charges $C$. In this work, based on symmetry analysis, low-energy effective models, and first-principles calculations, we identify charge-two cubic lattices. We first derive minimal lattice model that exhibits a single pair Weyl points opposite $C=\ifmmode\pm\else\textpm\fi{}2$. Furthermore, show ultralight crystal ${\mathrm{P}4}_{3}32$-type...

Two new α1-phase monolayers (MoSi 2 Sb 4 and WSi ) a family α2-phase monolayer MSi Z (M = Mo, W; P, As, Sb) was proposed by first-principles calculations.

Applying electric or magnetic fields is widely used to not only create and manipulate topological states but also facilitate their observations in experiments. In this work, we show by first-principles calculations analysis that the time-reversal (TR) symmetry-broken quantum spin Hall (QSH) state emerges a two-dimensional ferromagnetic MnBi$_4$Te$_7$ monolayer. This TR-symmetry broken QSH phase possesses highly tunable nontrivial band gap under an external field (or tuning interlayer...