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arXiv 1601.07908cond-mat.mes-hallcond-mat.str-elcond-mat.supr-con
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Majorana纳米线拓扑相变的研究

Approaching a topological phase transition in Majorana nanowires

Ryan V. Mishmash, David Aasen, Andrew P. Higginbotham, Jason Alicea

摘要:

最近的实验已经产生了越来越多的证据马约拉纳零模式的超导体混合体。然而,伴随着这些模式的发病预期的拓扑相变的签名仍然难以捉摸。我们调查一个基本的问题,关于这个问题:良好形成的马约拉纳模式一定需要一个尖锐的相变在这些设置?假设合理的参数,我们认为,有限大小的影响可以显着平滑这个假定的过渡到一个交叉,即使在系统大到足以支持本地化的马约拉纳模式。我们建议克服这种有限尺寸的影响,通过隧道光谱检查低的激发态的行为。特别是,激发态能量表现出特征场和密度的依赖性,并与系统大小的缩放,暴露了接近的拓扑相变。我们建议几个实验提取预测的行为。作为一个有用的副产品,该协议还允许人们在其超导环境中直接测量导线的自旋轨道耦合。

英文摘要:

Recent experiments have produced mounting evidence of Majorana zero modes in nanowire-superconductor hybrids. Signatures of an expected topological phase transition accompanying the onset of these modes nevertheless remain elusive. We investigate a fundamental question concerning this issue: Do well-formed Majorana modes necessarily entail a sharp phase transition in these setups? Assuming reasonable parameters, we argue that finite-size effects can dramatically smooth this putative transition into a crossover, even in systems large enough to support well-localized Majorana modes. We propose overcoming such finite-size effects by examining the behavior of low-lying excited states through tunneling spectroscopy. In particular, the excited-state energies exhibit characteristic field and density dependence, and scaling with system size, that expose an approaching topological phase transition. We suggest several experiments for extracting the predicted behavior. As a useful byproduct, the protocols also allow one to measure the wire's spin-orbit coupling directly in its superconducting environment.

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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