时间反演不变拓扑态的发现在近几十年来引起了人们的极大关注。然而,尽管有潜力展示各种奇异的物理,磁拓扑相位的研究滞后,由于潜在的增加了磁性的复杂性。在这项工作中,我们预测的磁性和拓扑结构的相互作用,在非中心对称的三元锰化合物MnIn $_2$ Te $_4$,使用第一性原理计算。在环境压力下,系统的基态是反铁磁绝缘体。随着应用程序的小静水压力($\sim$ 0.50 GPa),它经历了磁性转变和铁磁状态变得积极有利。在$\sim$ 2.92 GPa下,系统经历了到外尔半金属相的过渡,该外尔半金属相在本体中具有多个外尔点,并且与非平凡的表面费米弧相关联。值得注意的是,我们发现,在这个系统中的外尔点的数量可以控制的压力,这些表现在一个异常的霍尔电导率(AHC)。除了提出一种新的候选磁性拓扑材料之外,我们的工作还表明,压力可以是在磁性材料中诱导和控制拓扑相以及AHC的有效方法。这些特性可以使我们提出的材料被用作一种新型的压力控制霍尔开关。
英文摘要:
The discovery of time-reversal-invariant topological states has drawn great attention in recent decades. However, despite the potential of displaying a variety of exotic physics, the study of magnetic topological phases lags behind due to underlying added complexity of magnetism. In this work, we predict the interplay of magnetism and topology in the non-centrosymmetric ternary manganese compound MnIn$_2$Te$_4$, using first-principles calculations. At ambient pressure, the ground state of the system is an antiferromagnetic insulator. With the application of small hydrostatic pressure ($\sim$0.50 GPa), it undergoes a magnetic transition and the ferromagnetic state becomes energetically favourable. At $\sim$2.92 GPa, the system undergoes a transition into a Weyl semimetallic phase, which hosts multiple Weyl points in the bulk and is associated with non-trivial surface Fermi arcs. Remarkably, we discover that the number of Weyl points in this system can be controlled by pressure and that these manifest in an anomalous Hall conductivity (AHC). In addition to proposing a new candidate magnetic topological material, our work demonstrates that pressure can be an effective way to induce and control topological phases, as well as AHC, in magnetic materials. These properties may allow our proposed material to be used as a novel pressure-controlled Hall switch.
Synchrotron x-ray diffraction and DFT study of non-centrosymmetric EuRhGe3 under high pressure
Institute of Physics(物理研究所);Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides(巴黎萨克雷大学、法国国家科学研究中心、固体物理实验室);Department of Physics, Faculty of Science, University of Zagreb(萨格勒布大学理学院物理系);Institute of Low Temperature and Structure Research, Polish Academy of Sciences(波兰科学院低温与结构研究所);Synchrotron SOLEIL(SOLEIL同步辐射中心);Department of Earth Sciences, Department of Physics and Astronomy, University of Western Ontario(韦斯顿安大略大学地球科学系、物理与天文学系)
Pressure-induced charge orders and their coupling to magnetism in hexagonal multiferroic LuFe2O4
六方晶系LuFe_2 O_4是一种具有高电荷和自旋有序温度的CO驱动的多铁性材料。Fe 3 +/Fe 2+位置上电荷和自旋序的共存导致了新颖的磁电行为,但电荷和自旋序之间的耦合机制仍不清楚。在这里,通过调节外压,我们揭示了三个相关的自旋电荷有序相LuFe 2 O 4:i)一个中心对称的无公度三维CO亚铁磁性,ii)一个非中心对称的无公度准二维CO亚铁磁性,和iii)一个中心对称的公度CO反铁磁性。结合密度泛函理论计算的X射线单晶衍射和X射线磁性圆二色性测量结果表明,在受抑双层[Fe 2 O 4]团簇中,压力诱导压缩引起的电荷密度重新分布是导致相关自旋-电荷相变的原因. Fe-Fe键间的有效库仑作用使(1/3,1/3)阻挫CO转变为阻挫较小的(1/4,1/4)CO,从而引起亚铁磁到反铁磁的转变。我们的结果不仅阐明了LuFe 2 O 4中电荷、自旋和晶格自由度之间的耦合机制,而且提供了一种新的方法来以高度可控的方式调节自旋-电荷有序。
The New High-entropy Compound RhMnFeCoGe4 with Cubic Non-centrosymmetric B20 Structure
Vereshchagin Institute for High Pressure Physics, RAS(俄罗斯科学院维列夏金高压物理研究所);Mikheev Institute of Metal Physics, Russian Academy of Sciences(俄罗斯科学院米凯耶夫金属物理研究所)
An underdog story: Re-emergence of a polar instability at high pressure in KNbO3
University of Luxembourg(卢森堡大学);Institut Néel CNRS/UGA UPR2940(格勒诺布尔神经科学研究所);Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504(斯特拉斯堡大学);ESRF – European Synchrotron Radiation Facility(欧洲同步辐射装置);Synchrotron SOLEIL(索雷尔同步辐射中心)
Pressure induced structural transitions, coordination crossover, and optoelectronic response in divalent metavanadate CaV$_2$O$_6$
Indian Institute of Science Education and Research Kolkata(印度科学教育研究学院加尔各答分校);National Centre for High-Pressure Studies(高压研究中心);IMPMC, Sorbonne Université(巴黎第六大学地球物理学研究所);Beijing Academy of Quantum Information Sciences(北京量子信息科学研究院);Deutsches Elektronen Synchrotron(德国电子同步辐射中心)
Evolution of Magnetism in Ce$_4$Ge$_7$ under Magnetic Field and Pressure
New Cornerstone Science Laboratory, Center for Correlated Matter and School of Physics, Zhejiang University(浙江大学关联物质中心与物理学院新基石科学实验室);Hubei Key Laboratory of Photoelectric Materials and Devices, School of Materials Science and Engineering, Hubei Normal University(湖北师范大学材料科学与工程学院光电材料与器件湖北省重点实验室)