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arXiv 2206.04065cond-mat.str-elcond-mat.supr-con
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二维拓扑超导体中可调谐的零能狄拉克节点与Luttinger节点

Tunable zero-energy Dirac and Luttinger nodes in a two-dimensional topological superconductor

Ryan Mays, Predrag Nikolic

AI总结:

本文研究二维拓扑超导体中自旋三重态配对态下的Bogoliubov准粒子谱,发现零能狄拉克节点可随序参量和自旋轨道耦合调谐,并分析了其合并打开能隙及实验特征。

摘要:

在拓扑绝缘体超薄膜中,由内禀机制或邻近效应诱导的Cooper配对可以产生能量上有利的自旋三重态超导态。自旋轨道耦合作为SU(2)规范场起作用,并在该超导态中促进自旋流涡旋晶格的形成。本文研究了这种态中的Bogoliubov准粒子,发现准粒子谱包含若干被粒子-空穴对称性钉扎在零能的狄拉克节点。其中一些节点是“偶然的”,随着序参量幅度或自旋轨道耦合强度的变化,它们会沿高对称方向在第一布里渊区中移动。在特定参数值下,形成中性四重态的节点会合并并打开能隙,暂时产生二次型能带接触谱。所有这些特征都可以通过异质结器件中的栅极电压控制序参量幅度来进行调谐。除了在平均场层面分析能谱外,我们还简要讨论了该能谱的若干实验特征。

英文摘要:

Cooper pairing in ultrathin films of topological insulators, induced intrinsically or by proximity effect, can produce an energetically favorable spin-triplet superconducting state. The spin-orbit coupling acts as an SU(2) gauge field and stimulates the formation of a spin-current vortex lattice in this superconducting state. Here we study the Bogoliubov quasiparticles in such a state and find that the quasiparticle spectrum consists of a number of Dirac nodes pinned to zero energy by the particle-hole symmetry. Some nodes are "accidental" and move through the first Brillouin zone along high-symmetry directions as the order parameter magnitude or the strength of the spin-orbit coupling are varied. At special parameter values, nodes forming neutral quadruplets merge and become gapped out, temporarily producing a quadratic band-touching spectrum. All these features are tunable by controlling the order parameter magnitude via a gate voltage in a heterostructure device. In addition to analyzing the spectrum at the mean-field level, we briefly discuss a few experimental signatures of this spectrum.

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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