物理学报2023，Vol.72Issue(24)：197-204,8.DOI:10.7498/aps.72.20231163
二维磁性半导体笼目晶格Nb3Cl8单层的磁性及自旋电子输运性质
Magnetism and spin transport properties of two-dimensional magnetic semiconductor kagome lattice Nb3Cl8 monolayer
摘要
Abstract
Two-dimensional semiconductor materials with intrinsic magnetism have great application prospects in realizing spintronic devices with low power consumption,small size and high efficiency.Some two-dimensional materials with special lattice structures,such as kagome lattice crystals,are favored by researchers because of their novel properties in magnetism and electronic properties.Recently,a new two-dimensional magnetic semiconductor material Nb3Cl8 monolayer with kagome lattice structure was successfully prepared,which provides a new platform for exploring two-dimensional magnetic semiconductor devices with kagome structure.In this work,we study the electronic structure and magnetic anisotropy of Nb3Cl8 monolayer.We also further construct its p-n junction diode and study its spin transport properties by using density functional theory combined with non-equilibrium Green's function method.The results show that the phonon spectrum of the Nb3Cl8 monolayer has no negative frequency,confirming its dynamic stability.The band gap of the spin-down state(1.157 eV)is significantly larger than that of the spin-up state(0.639 eV).The magnetic moment of the Nb3Cl8 monolayer is 0.997 μB,and its easy magnetization axis is in the plane and along the x-axis direction based on its energy of magnetic anisotropy.The Nb atoms make the main contribution to the magnetic anisotropy.When the strain is applied,the band gap of the spin-down states will decrease,while the band gap of the spin-up state monotonically decreases from the negative(compress)to positive(tensile)strain.As the strain variable goes from-6％to 6％,the contribution of Nb atoms to the total magnetic moment gradually increases.Moreover,strain causes the easy magnetization axis of the Nb3Cl8 monolayer to flip vertically from in-plane to out-plane.The designed p-n junction diode nanodevice based on Nb3Cl8 monolayer exhibits an obvious rectification effect.In addition,the current in the spin-up state is larger than that in the spin-down state,exhibiting a spin-polarized transport behavior.Moreover,a negative differential resistance(NDR)phenomenon is also observed,which could be used in the NDR devices.These results demonstrate that the Nb3Cl8 monolayer material has great potential applications in the next-generation high-performance spintronic devices,and further experimental verification and exploration of this material and related two-dimensional materials are needed.关键词
Nb3Cl8单层/磁性材料/磁各向异性/自旋电子输运Key words
Nb3Cl8 monolayer/magnetic material/magnetic anisotropy/spin electron transport引用本文复制引用
樊晓筝,李怡莲,吴怡,陈俊彩,徐国亮,安义鹏..二维磁性半导体笼目晶格Nb3Cl8单层的磁性及自旋电子输运性质[J].物理学报,2023,72(24):197-204,8.基金项目
国家自然科学基金(批准号:12274117)、河南省高校科技创新团队(批准号:24IRTSTHN025)、河南省优秀青年科学基金(批准号:202300410226)、中原英才计划-中原青年拔尖人才项目(2021年)、河南省高校重点科研项目(批准号:22A140020)和河南省外籍专家工作室项目(批准号:GZS2023007)资助的课题.Project supported by the National Natural Science Foundation of China(Grant No.12274117),the Program for Innovative Research Team(in Science and Technology)in University of Henan Province,China(Grant No.24IRTSTHN025),the Science Foundation for the Excellent Youth Scholars of Henan Province,China(Grant No.202300410226),the Young Top-notch Talents Project of Henan Province,China(2021 year),the Key Scientific Project of Universities of Henan Province,China(Grant No.22A140020),and the Henan Center for Outstanding Overseas Scientists,China(Grant No.GZS2023007). （批准号:12274117）
