掺杂量子自旋霍尔态后所形成超导的平均场计算  

Mean-field calculation of the doping-iduced quantum spin Hall state to superconductor transiton

作　　者：侯迪莎 郭文安[1] HOU Disha;GUO Wen’an(Department of Physics,Beijing Normal University,Beijing,China)

机构地区：[1]北京师范大学物理学系,北京

出　　处：《北京师范大学学报（自然科学版）》2024年第1期1-8,共8页Journal of Beijing Normal University(Natural Science)

基　　金：国家自然科学基金资助项目(12175015,11734002)。

摘　　要：给出了对易面t-λ模型详细平均场理论和计算的结果,特别是给出了平均场相图.研究表明,掺杂纯的量子自旋霍尔(QSH)态后可获得2种结论:1)相互作用强度较弱时,QSH态和超导态之间可发生一级相变;2)相互作用强度较强时,系统经过一个连续相变进入2相共存区,并发生QSH态消失的一级相变.计算结果表明,平均场理论虽然体现了对称破缺相的特征,但是其忽略了涨落,致使其得到QSH态与超导态共存的错误结论,从而使得平均场理论无法准确描述因拓扑激发所引起的相变.The mean-field theory and simulation result of the easy-plane t-λmodel and the mean-field phase diagram are given in this paper.Two mean-field scenarios exist for doping the pure QSH state:1)a first-order QSHSSC transition occurs in the weak interaction region;2)a continuous QSH to QSH-SSC co-existence transition followed by a first-order QSH-vanishing transition in the strong interaction region.The mean-field theory is found to capture features for symmetry-broken phases but give the wrong conclusion of QSH-SSC co-existence due to ignoring fluctuation.It is unable to characterize transitions with topological excitation.

关 键 词：量子强关联 量子自旋霍尔态 超导 掺杂 平均场计算 

分 类 号：O414.21[理学—理论物理]