摘要
探索低维体系电子态的调控规律可以为构筑下一代微纳电子学器件提供理论基础.本文采用第一性原理计算研究了一维螺旋型Se原子链的结构性质和电子性质.结果发现,该结构比直线型结构能量要低得多,且具有动力学和热力学稳定性.能带计算表明,这种螺旋型一维原子链结构是带隙约为2.0 eV的半导体,且在X点附近展现出Rashba型的自旋劈裂.这种特殊的原子链结构便于人们通过应力调控其电子性质.计算结果表明,5%的拉伸应变就可以将其带隙减小20%,而5%的压缩应变将Rashba能量偏移增大到平衡体积时的2倍多.此外,其价带是一条平带,引入空穴掺杂可以诱导产生磁性,从而使体系转变为半金属.进一步增加空穴掺杂,体系转变为铁磁金属.同样,这种掺杂效应还出现在一维螺旋型Te原子链中.
Tuning the electronic properties of low-dimensional materials is helpful in building nano electronic devices.Here, we investigate the structural and electronic structures of one-dimensional helical Se atomic chain by using first-principles calculations. Our results show that this structure has a much lower energy than the one with a straight-line structure. Our phonon calculations and ab initio molecular dynamics simulations suggest that this structure is both dynamically and thermally stable. The band structure shows that it is a semiconductor with a gap of about 2.0 eV and Rashba-type splitting near the X point. The helical structure is good for tuning the electronic properties by using strains. As a result, a 5% strain leads to a 20% change in the band gap while the Rashba energy offset is doubled. Moreover, we find that the valence band is a flat band, over which hole doping can induce ferromagnetism and the system becomes half-metallic. Further increasing the doping level can transform the system into a ferromagnetic metal. Such a strategy is then applied to one-dimensional helical Te atomic chain and similar results are obtained.
作者
孙海明
Sun Hai-Ming(School of Physics and Electronics,Hunan Normal University,Changsha 410081,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第14期229-234,共6页
Acta Physica Sinica
关键词
一维原子链
RASHBA
效应
电子结构
应力调控
平带
one-dimensional atomic chain
Rashba effect
electronic structure
strain tuning
flat band
