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arXiv 1012.0330cond-mat.supr-concond-mat.str-el
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掺杂拓扑绝缘体中超导涡旋端部的Majorana模

Majorana modes at the ends of superconductor vortices in doped topological insulators

Pavan Hosur, Pouyan Ghaemi, Roger S. K. Mong, Ashvin Vishwanath

摘要:

最近的实验已经在掺杂的拓扑绝缘体中观察到了体超导性。在这里,我们问是否涡马约拉纳零模式,以前预测发生时,超导性诱导的表面上的拓扑绝缘体,生存,即使在这些掺杂系统与金属正常状态。假设反转对称,我们发现,马约拉纳零模式确实出现,但只有低于临界掺杂。临界掺杂与涡线的拓扑相变相关,在那里它支持沿其长度的无间隙激发。临界点仅取决于涡旋线的取向和Berry相的性质,即金属正常态费米面的SU(2)Berry相。通过计算可用能带结构的该相位,我们确定了诸如$p$掺杂的Bi $_{2}$ Te $_{3}$的材料候选物在压力下支持涡旋端Majorana模式。令人惊讶的是,即使是从拓扑上平凡的能带结构衍生的超导体也可以支持马约拉纳模式,这为实现它们提供了一条有前途的途径。

英文摘要:

Recent experiments have observed bulk superconductivity in doped topological insulators. Here we ask whether vortex Majorana zero modes, previously predicted to occur when superconductivity is induced on the surface of topological insulators, survive even in these doped systems with metallic normal states. Assuming inversion symmetry, we find that Majorana zero modes indeed appear but only below a critical doping. The critical doping is associated with a topological phase transition of the vortex line, where it supports gapless excitations along its length. The critical point depends only on the orientation of the vortex line, and a Berry phase property, the SU(2) Berry phase of the Fermi surface in the metallic normal state. By calculating this phase for available band structures we determine that materials candidates like $p$-doped Bi$_{2}$Te$_{3}$ under pressure supports vortex end Majorana modes. Surprisingly, even superconductors derived from topologically trivial band structures can support Majorana modes, providing a promising route to realizing them.

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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