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arXiv 1502.03680cond-mat.str-elcond-mat.mes-hall
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拓扑绝缘体中的反常自旋动力学

Unusual spin dynamics in topological insulators

Balázs Dóra, Ferenc Simon

摘要:

在弱自旋轨道耦合的常规材料中,动态自旋极化率(DSS)具有普遍存在的洛伦兹形式,其谱宽表征了自旋弛豫速率。结果表明,在具有强SOC的拓扑绝缘体中,DSS具有一种特殊的非洛仑兹形式.在零温下,DSS的高频部分是普遍的,并且在某些方向上分别以$ω^{d-1}$ + $d=2$和3的形式增加,而对于螺旋边缘态,相互作用将DSS的指数重整化为$d=2K-1$ + $K$ + Luttinger液体参数.因此,自旋弛豫速率不能从DSS中推导出,与通常的金属的情况相反,这是由于这些系统中的自旋和电荷自由度强烈纠缠。这些与中性石墨烯的光学电导率平行。

英文摘要:

The dynamic spin susceptibility (DSS) has a ubiquitous Lorentzian form in conventional materials with weak spin orbit coupling, whose spectral width characterizes the spin relaxation rate. We show that DSS has an unusual non-Lorentzian form in topological insulators, which are characterized by strong SOC. At zero temperature, the high frequency part of DSS is universal and increases in certain directions as $ω^{d-1}$ with $d=2$ and 3 for surface states and Weyl semimetals, respectively, while for helical edge states, the interactions renormalize the exponent as $d=2K-1$ with $K$ the Luttinger-liquid parameter. As a result, spin relaxation rate cannot be deduced from the DSS in contrast to the case of usual metals, which follows from the strongly entangled spin and charge degrees of freedom in these systems. These parallel with the optical conductivity of neutral graphene.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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