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arXiv 1502.03664cond-mat.supr-concond-mat.str-el
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拓扑超导体中的准粒子干涉花样

Quasiparticle Interference Patterns in a Topological Superconductor

Aaron Farrell, Maxime Beaudry, M. Franz, T. Pereg-Barnea

摘要:

针对在强拓扑绝缘体表面实现拓扑超导体的新设想,我们研究了二维拓扑超导中的杂质散射和涡旋散射。本文在三维强拓扑绝缘体的表面模型中发展了一个准粒子干涉理论。我们考虑了各种不同的散射体,包括磁性和非磁性杂质以及与涡核存在相关的局部配对序参量抑制。类似于三维拓扑绝缘体的表面没有配对的情况下,我们的非磁性杂质的结果可以解释的情况下,背散射,如预期的狄拉克锥结构。在超导的情况下,远离狄拉克点的掺杂导致恒定能量的轮廓加倍。这与未成对的情况相反,在未成对的情况下,化学势简单地增加到偏置电压并转移能量。这种等值线的加倍导致每个能量中可能的散射过程的数量成倍增加。有趣的是,我们发现,一些过程是占主导地位的杂质的情况下,而其他占主导地位的涡旋的情况下。此外,这两种类型的过程导致对化学势的不同依赖性。

英文摘要:

In light of recent proposals to realize a topological superconductor on the surface of strong topological insulators, we study impurity and vortex scattering in two dimensional topological superconductivity. We develop a theory of quasiparticle interference in a model of the surface of a three dimensional strong topological insulator with a pairing term added. We consider a variety of different scatterers, including magnetic and nonmagnetic impurity as well as a local pairing order parameter suppression associated with the presence of a vortex core. Similar to the case of a surface of a three dimensional topological insulator without pairing, our results for non-magnetic impurity can be explained by the absence of back scattering, as expected for a Dirac cone structure. In the superconducting case, doping away from the Dirac point leads to a doubling of the contours of constant energy. This is in contrast to the unpaired case where the chemical potential simply adds to the bias voltage and shifts the energy. This doubling of contours results in multiplying the number of possible scattering processes in each energy. Interestingly, we find that some processes are dominant in the impurity case while others are dominant in the vortex case. Moreover, the two types of processes lead to a different dependence on the chemical potential.

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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