Quantum Anomalous Hall Effects Controlled by Chiral Domain Walls

We report the interplay between two different topological phases in condensed matter physics,the magnetic chiral domain wall(DW),and the quantum anomalous Hall(QAH)effect.It is shown that the chiral DW driven by Dzyaloshinskii–Moriya interaction can divide the uniform domain into several zones where the neighboring zone possesses opposite quantized Hall conductance.The separated domain with a chiral edge state(CES)can be continuously modified by external magnetic field-induced domain expansion and thermal fluctuation,which gives rise to the reconfigurable QAH effect.More interestingly,we show that the position of CES can be tuned by spin current driven chiral DW motion.Several two-dimensional magnets with high Curie temperature and large topological band gaps are proposed for realizing these phenomena.The present work thus reveals the possibility of chiral DW controllable QAH effects.

Strain-Enabled Control of Chiral Magnetic Structures in MnSeTe Monolayer

Chiral magnetic states are promising for future spintronic applications. Recent progress of chiral spin textures in two-dimensional magnets, such as chiral domain walls, skyrmions, and bimerons, have been drawing extensive attention. Here, via first-principles calculations, we show that biaxial strain can effectively manipulate the magnetic parameters of the Janus Mn Se Te monolayer. Interestingly, we find that both the magnitude and the sign of the magnetic constants of the Heisenberg exchange coupling, Dzyaloshinskii–Moriya interaction and magnetocrystalline anisotropy can be tuned by strain. Moreover, using micromagnetic simulations, we obtain the distinct phase diagram of chiral spin texture under different strains. Especially, we demonstrate that abundant chiral magnetic structures including ferromagnetic skyrmion, skyrmionium, bimeron, and antiferromagnetic spin spiral can be induced in the Mn Se Te monolayer. We also discuss the effect of temperature on these magnetic structures. The findings highlight the Janus Mn Se Te monolayer as a good candidate for spintronic nanodevices.

Mechanism of"Five Meridians Acupuncture"in Treating Postoperative Urinary Retention after Anorectal Diseases

In recent years,with the change of rhythm and eating habits of the public,the number of patients with anorectal diseases has gradually increased,and postoperative urinary retention has also become more common.Urinary retention refers to the symptoms of anorectal diseases and is caused by improper urination and incompletion of urination due to surgical and pain causes that result in bladder and urine filling and are accompanied by lower abdominal distention and pain.In traditional Chinese medicine,acupuncture is simple and effective as a treatment.In this article,we focus on five meridians that pass through the lower abdomen Ren meridian,kidney meridian,spleen meridian,stomach meridian,and liver meridian,namely the"five meridians,"and study the mechanism of action so as to provide new therapeutic ideas for clinical acupuncture treatment of postoperative urinary retention of anorectal diseases.

Advances in the Medicinal Value of Constructed Wetland Plants for Treating Rural Domestic Sewage

Firstly,the advantages and disadvantages of constructed wetlands for treating rural domestic sewage are introduced.Secondly,the types of constructed wetland plants are introduced.Thirdly,the suitability of using medicinal wetland plants to treat rural domestic sewage is analyzed.Fourthly,the principles of selecting wetland plants with medicinal value are studied.Finally,commonly used constructed wetland plants and their medicinal value are introduced.

Progress in the Treatment of Edema After Surgery for Mixed Hemorrhoids

Edema is a common postoperative complication in mixed hemorrhoids.With the development of medical treatment,surgical improvement has greatly reduced surgical trauma to the body,but the issue of postoperative edema still exists.In order to explore the treatment progress of edema after surgery for mixed hemorrhoids,literatures on integrated traditional Chinese and western medicine for postoperative edema in hemorrhoids have been reviewed in hope to better understand the complication and provide reference for relevant clinical studies in the future.

合成铁磁多层膜中各向异性层间Dzyaloshinski-Moriya相互作用

Dzyaloshinskii-Moriya相互作用(DMI)在合成磁性多层膜体系和自旋电子技术中扮演着重要的作用.这种非共线相互作用在磁性多层膜体系中包括两种形式:界面DMI和层间DMI.对于界面DMI,其单易轴性和各向异性特征都已被发现,为拓扑自旋的技术发展奠定了基础.然而,到目前为止,有关层间DMI的研究都是单易轴性的,层间DMI的各向异性特征尚未报道.本文结合实验和理论结果,报道了[Co/Pd]多层结构中的各向异性层间DMI,这种层间手性相互作用可引起在互为60°的两个方向上的非对称磁化翻转行为.第一性原理计算表明,层间DMI的各向异性是由面心立方结构中沿(111)面两个能量较低的高对称方向上的面内反演对称性破缺导致.各向异性层间DMI的发现不仅揭示了磁性多层膜中长程层间耦合相互作用的起源,也为基于磁性多层膜的自旋电子学器件设计提供了新的途径.

Magnetic anisotropy,exchange coupling and Dzyaloshinskii–Moriya interaction of two-dimensional magnets

The two-dimensional(2D)magnets provide novel opportunities for understanding magnetism and investigating spin related phenomena in several atomic thickness.Multiple features of 2D magnets,such as critical temperatures,magnetoelectric/magneto-optic responses,and spin configurations,depend on the basic magnetic terms that describe various spins interactions and cooperatively determine the spin Hamiltonian of studied systems.In this review,we present a comprehensive survey of three types of basic terms,including magnetic anisotropy that is intimately related with longrange magnetic order,exchange coupling that normally dominates the spin interactions,and Dzyaloshinskii–Moriya interaction(DMI)that favors the noncollinear spin configurations,from the theoretical aspect.We introduce not only the physical features and origin of these crucial terms in 2D magnets but also many correlated phenomena,which may lead to the advance of 2D spintronics.

A simple and efficient criterion for ready screening of potential topological insulators

Topological materials are a new and rapidly expanding class of quantum matter. To date, identification of the topological nature of a given compound material demands specific determination of the appropriate topological invariant through detailed electronic structure calculations. Here we present an efficient criterion that allows ready screening of potential topological materials, using topological insulators as prototypical examples. The criterion is inherently tied to the band inversion induced by spin-orbit coupling,and is uniquely defined by a minimal number of two elemental physical properties of the constituent elements: the atomic number and Pauling electronegativity. The validity and predictive power of the criterion is demonstrated by rationalizing many known topological insulators and potential candidates in the tetradymite and half-Heusler families, and the underlying design principle is naturally also extendable to predictive discoveries of other classes of topological materials.

Anisotropic Dzyaloshinskii-Moriya interaction protected by D_(2d) crystal symmetry in two-dimensional ternary compounds

Magnetic skyrmions,topologically protected chiral spin swirling quasiparticles,have attracted great attention in fundamental physics and applications.Recently,the discovery of two-dimensional(2D)van der Waals(vdW)magnets have aroused great interest due to their appealing physical properties.Moreover,both experimental and theoretical works have revealed that isotropic Dzyaloshinskii–Moriya interaction(DMI)can be achieved in 2D magnets or ferromagnet-based heterostructures.However,2D magnets with anisotropic DMI haven’t been reported yet.Here,via using first-principles calculations,we unveil that anisotropic DMI protected by D_(2d)crystal symmetry can exist in 2D ternary compounds MCuX_(2)(M:3d transition metal(TM),X:group VIA).Interestingly,by using micromagnetic simulations,we demonstrate that ferromagnetic(FM)antiskyrmions,FM bimerons,antiferromagnetic(AFM)antiskyrmions,and AFM bimerons can be realized in the MCuX_(2)family.Our discovery opens up an avenue to creating antiskyrmions and bimerons with anisotropic DMI protected by D_(2d)crystal symmetry in 2D magnets.