WSeTe/CrI_(3)范德瓦耳斯异质结能谷的调控  

Valley manipulation in WSeTe/CrI_(3) van der Waals heterostructures:A first-principles study

作　　者：廖玉民 陈许敏 徐黄雷 易水生 王辉 霍德璇[2] LIAO Yumin;CHEN Xumin;XU Huanglei;YI Shuisheng;WANG Hui;HUO Dexuan(School of Science,Hangzhou Dianzi University,Hangzhou 310018,China;School of Materials and Environmental Engineering,Hangzhou Dianzi University,Hangzhou 310018,China)

机构地区：[1]杭州电子科技大学理学院,杭州310018 [2]杭州电子科技大学材料与环境工程院,杭州310018

出　　处：《物理学报》2025年第9期292-301,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11874011)资助的课题.

摘　　要：范德瓦耳斯异质结构为设计二维材料的电子、自旋特性提供了丰富的平台.解除谷简并是利用谷自由度处理和存储谷电子信息的必要条件,二维范德瓦耳斯异质结构中的邻近效应为定制邻近材料的电子能带结构提供了可控的方法.本文基于第一性原理计算,研究了WSeTe/CrI_(3)范德瓦耳斯异质结的电子能带结构.通过施加垂直应变与改变衬底磁矩方向对能谷进行调控.单层WSeTe在K与K'存在一对简并能谷,在自旋-轨道耦合作用与磁性衬底CrI_(3)邻近效应作用下会产生较大的谷劈裂和谷极化.异质结产生的谷极化为25 meV.施加垂直应变可以有效地调节能谷极化,减小层间距可以增大谷极化.此外,衬底磁矩方向变化可以有效调控谷极化的方向和大小.本文研究结果为谷自由度的调控提供了一个有效的方法,为谷电子学和自旋电子学的应用提供了新的途径.The valley degree of freedom,besides charge and spin,can be used to process information and perform logic operations as well,with the advantage of low power consumption and high speed.The effective manipulation of valley degrees of freedom is essential for their practical applications in valleytronics and spintronics.In this work,the effective strategy is investigated for the valley manipulation of the WSeTe/CrI_(3) van der Waals heterojunction with about 2%lattice mismatch by the first-principles calculations.The valley degree of freedom in WSeTe can be modulated by the magnetism of Cr atoms in the substrate via the magnetic proximity effect,including the vertical strain method and the rotation of the magnetic moments of Cr atoms.First-principles calculations are performed by using the VASP software package with the generalized gradient approximation functional in PerdewBurke-Ernzerhof(PBE)form.The spin-orbit coupling is considered when calculating the band structure to investigate the valley properties.The dependence of valley polarization on both vertical strain and the substrate’s magnetic moment direction has been systematically analyzed.There are two different stacking configurations for the WSeTe/CrI_(3) heterojunction with Te/Se atoms at the interface,namely Te-stacking and Se-stacking.Although single-layer WSeTe does not have valley polarization,the Te-stacked and Se-stacked WSeTe/CrI_(3) heterojunctions exhibit valley polarizations of 25 meV and 2 meV,respectively,which is influenced by spin-orbit coupling and the proximity effect of the magnetic substrate CrI_(3),indicating the importance of the stack configuration.The Te-stacked configuration of the heterojunction has a larger valley polarization due to stronger orbital hybridization between W atoms in WSeTe layer and Cr atoms in CrI_(3) layer.The application of vertical strain,which effectively tunes the interlayer distance,significantly regulates the valley polarization.Specifically,the valley polarization is increased to 59 meV when the interlaye

关 键 词：能谷 异质结 磁近邻 第一性原理 

分 类 号：O469[理学—凝聚态物理]