High-temperature nodal ring semimetal in two-dimensional honeycomb-kagome Mn_(2)N_(3) lattice

The search for two-dimensional(2D)nodal ring semimetallic materials is a current research hotspot in spintronics,and designing a 2D nodal ring(NR)material with high Curie temperature(TC)and strong robustness to spin-orbit coupling(SOC)is an even greater challenge.Here,based on the first-principles calculations and symmetry analysis,we predict that 2D Mn_(2)N_(3)is a nodal ring semimetal(NRSM)with three energy bands near the Fermi energy level consisting of electrons in the same spin channel.An electron-like energy band and two hole-like energy bands near the Fermi plane cross to form two NRs centered at the pointΓ.Symmetry analysis shows that the spin-polarized NR semimetal is robust to SOC due to the conservation of horizontal mirror symmetry.Monte-Carlo simulations further demonstrate that the TCof the 2D Mn_(2)N_(3)reaches 530 K,well above the room temperature.Notably,the 2D Mn_(2)N_(3)remains an NRSM on h-BN substrate.Our results not only reveal a general framework for designing 2D NR materials,but also promote further research in the direction of multifunctional quantum devices for spintronics.

Spin–orbit stable dirac nodal line in monolayer B_(6)O

The two-dimensional(2D) materials with nodal line band crossing have been attracting great research interest. However, it remains a challenge to find high-stable nodal line structure in 2D systems. Herein, based on the first-principles calculations and theoretical analysis, we propose that monolayer B_(6)O possesses symmetry protected Dirac nodal line(DNL)state, with its Fermi velocity of 10^(6)m/s in the same order of magnitude as that of graphene. The origin of DNL fermions is induced by coexistence of time-reversal symmetry and inversion symmetry. A two-band tight-binding model is further given to understand the mechanism of DNL. Considering its robustness against spin–orbit coupling(SOC) and high structural stability, these results suggest monolayer B_(6)O as a new platform for realizing future high-speed low-dissipation devices.

Discovery of Two-Dimensional Quantum Spin Hall Effect in Triangular Transition-Metal Carbides

Though the quantum spin Hall effect（QSHE） in two-dimensional（2 D） crystals has been widely explored, the experimental realization of quantum transport properties is only limited to HgTe/CdTe or InAs/GaSb quantum wells. Here we employ a tight-binding model on the basis of d（z^2）, d（xy）, and d（x^2-y^2） orbitals to propose QSHE in the triangular lattice, which are driven by a crossing of electronic bands at the Γ point. Remarkably, 2 D oxidized Mxenes W2 M2 C3 are ideal materials with nontrivial gap of 0.12 eV, facilitating room-temperature observations in experiments. We also find that the nontrivially topological properties of these materials are sensitive to the cooperative effect of the electron correlation and spin-orbit coupling. Due to the feasible exfoliation from its 3 D MAX phase, our work paves a new direction towards realizing QSHE with low dissipation.

Integrated bioinformatics analysis of key candidate genes and therapeutic drugs for idiopathic pulmonary fibrosis

Background: Idiopathic pulmonary fibrosis is a form of fibrotic and fatal lung disease worldwide with unknownetiology and mechanisms. This manuscript focused on clarifying the core protein-protein interaction network, genesand related pathways correlated with idiopathic pulmonary fibrosis in detail. Methods: Gene chip (GSE24206) wasacquired from the Gene Expression Omnibus database. GEO2R was a R-based online tool to screen differentialexpressed genes. Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analysis were utilized toascertain gene function and key signaling pathways. The Search Tool for the Retrieval of Interacting Genes was usedto construct the protein-protein interaction network. Key genes and module analysis were screened out usingCytohubba and MCODE plugin. The candidate therapeutic molecular drugs were searched for IPF using DGIdbdatabase. Results: A cohort of 240 differential expression of genes (113 up-regulated and 127 down-regulated) wereknocked out. Gene Ontology enrichment analysis indicated that some differential expression of genes were involvedin extracellular matrix and neutrophil chemotaxis. The Kyoto Encyclopedia of Genes and Genomes pathways werepredominantly involved in chemokine signaling pathway and ECM-receptor interactions. Two significant modulesand 5 hub genes were strongly implicated in idiopathic pulmonary fibrosis from protein-protein interaction network.The 2 module genes were primarily enriched in the cytokine-cytokine receptor, TNF signaling pathway, toll-likesignaling pathway, and Wnt signaling pathway. Finally, 41 small molecules were identified by DGIdb database as thepotential drugs of idiopathic pulmonary fibrosis. Conclusion: To conclude, in this study, the hub genes, signalingpathways, and small molecules will conduce to better understanding the mechanisms and may provide new methodsto the therapy of idiopathic pulmonary fibrosis.

Low-energy electronic properties of a Weyl semimetal quantum dot

We investigate the low-energy electronic structure ofa Weyl semimetal quantum dot （QD） with a simple model Hamiltonian with only two Weyl points. Distinguished from the semiconductor and topological insulator QDs, there exist both surface and bulk states near the Fermi level in Weyl semimetal QDs. The surface state, distributed near the side surface of the QD, contributes a circular persistent current, an orbital magnetic moment, and a chiral spin polarization with spin-current locking. There are always surface states even for a strong magnetic field, even though a given surface state gradually evolves into a Landau level with increasing magnetic field. It indicates that these unique properties can be tuned via the QD size. In addition, we show the correspondence to the electronic structures of a three-dimensional Weyl semimetal, such as Wey[ point and Fermi arc. Because a QD has the largest surface-to-volume ratio, it provides a new platform to verify Weyl semimetal by separating and detecting the signals of surface states. Besides, the study of Weyl QDs is also necessary for potential applications in nanoelectronics.