具有多种性质的新型二维Janus家族:拉胀行为、应变可调的光催化剂、高居里温度铁磁体和压电量子反常霍尔绝缘体
A new 2D Janus family with multiple properties:auxetic behavior,strain-tunable photocatalyst,high Curie temperature ferromagnets,and piezoelectric quantum anomalous Hall insulator
刘宇 1王帅宇 1李锋钰1
作者信息
- 1. School of Physical Science and Technology,Inner Mongolia University,Hohhot 010021,China
- 折叠
摘要
发现新的二维材料并探索其独特性质与潜在应用是凝聚态物理与材料科学的重要课题.在此,我们基于在实验和计算中报道的具有多种性质的新型方晶格S-XS2二维材料,通过密度泛函理论计算,确定了7种具有近似方晶格的新型二维Janus S-XSSe(X=Si,Sn,V,Cr,Mo,Re和Os)单层材料.值得注意的是,S-SiSSe和S-SnSSe单层都具有拉胀行为,此外,由于具有合适的带边位置、可见光区的高效吸收系数和较大的载流子迁移率差,它们是潜在的光催化剂,而且光催化性能还可以通过改变pH值和施加双轴应变来提高.在不考虑自旋轨道耦合(SOC)时,S-VSSe,S-CrSSe和S-MoSSe是铁磁半金属,并具有较高的居里温度Tc(分别为210,810和390 K).加入SOC后,S-VSSe成为量子反常霍尔(QAH)绝缘体,具有较大的带隙(45.4 meV)和一个手性边缘态(陈数C=-1).通过对半导体S-XSSe(X=Si,Sn,V)单层的对称性分析,基底面上的单轴应变只能诱发面外压电响应.其中,S-VSSe的面外压电系数d31和d32最大,分别为-0.013和0.025 pm V-1.压电性、拓扑性和铁磁性的共存使单层S-VSSe成为具有大带隙和高Tc的多功能自旋电子学应用的潜在平台.我们的理论工作将给二维材料增添新家族,并有望带来更广阔的应用.
Abstract
Discovering new two-dimensional(2D)mate-rials,exploring their unique properties and potentials in various applications are of paramount importance to con-densed matter physics and materials science.Here based on the diverse properties of the novel square lattice S-XS2 mate-rials found in experiments and computations,we identified 7 novel 2D Janus S-XSSe(X=Si,Sn,V,Cr,Mo,Re,Os)monolayers by means of density functional theory computa-tions.Remarkably,both S-SiSSe and S-SnSSe monolayers possess the auxetic behavior.In addition,they can act as po-tential photocatalysts,and their photocatalytic performance can be enhanced by changing the pH and applying biaxial strains.Without spin-orbit coupling(SOC),the S-VSSe,S-CrSSe,and S-MoSSe are ferromagnetic half-metals,and have high Curie temperatures Tc(210,810,and 390 K,respec-tively).When SOC is included,the S-VSSe becomes a quantum anomalous Hall insulator with a sizable gap(45.4 meV)and one chiral edge state(Chern number C=-1).By symmetry analysis of semiconducting S-XSSe(X=Si,Sn,V)monolayers,only out-of-plane piezoelectric response can be induced by a uniaxial strain in the basal plane,and among them,S-VSSe has both the largest out-of-plane piezoelectric coefficients d31 and d32,with values of-0.013 and 0.025 pm V-1,respectively.The concurrence of ferromagnetism,topology,and piezoelectricity empowers the S-VSSe monolayer as a potential platform for multi-functional spintronics applications with a large gap and high Tc.This theoretical work brings new members,also manifoldness in the properties and functions to the renown 2D materials family.
关键词
two-dimensional Janus structure/square transition metal dichalcogenides/negative Poisson's ratio/quantum anomalous Hall effect/photocatalyst/piezoelectricity/density functional theoryKey words
two-dimensional Janus structure/square transition metal dichalcogenides/negative Poisson's ratio/quantum anomalous Hall effect/photocatalyst/piezoelectricity/density functional theory引用本文复制引用
基金项目
国家自然科学基金(11964024)
国家自然科学基金(12364038)
the"Grassland Talents"Project of Inner Mongolia Autonomous Region(12000-12102613)
Young Science and Technology Talents Cultivation Project of Inner Mongolia University(21200-5223708)
computational support from the PARATEAR at Guangzhou Supercomputer Center()
出版年
2024
NETL
NSTL
万方数据