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arXiv 1402.4898cond-mat.supr-con
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超导拓扑绝缘体隧穿谱的准经典理论

Quasi-classical theory of tunneling spectroscopy in superconducting topological insulator

Shota Takami, Keiji Yada, Ai Yamakage, Masatoshi Sato, Yukio Tanaka

摘要:

本文发展了超导拓扑绝缘体(STI)的隧穿谱理论,即载流子掺杂拓扑绝缘体的超导态。基于准经典近似,我们得到了表面Andreev束缚态(ABS)的能量色散的解析表达式和正常金属/STI结隧穿电导的简洁公式.所得到的隧穿电导的简洁公式使实验数据的分析变得容易。作为我们理论的应用,我们研究了Cu $_x$ Bi $_2$ Se $_3$的隧穿电导。我们揭示了我们的理论再现了Yamakage { \it et al} [Phys. Rev. B 85,180509(R)(2012)]的先前结果。我们进一步研究了在外加磁场中准粒子的能量由于多普勒效应而移动的磁隧道谱。通过旋转基面上的磁场,我们可以在磁隧穿谱中区分两种不同的拓扑超导态,即有和没有点节点。

英文摘要:

We develop a theory of tunneling spectroscopy in superconducting topological insulator (STI), i.e. superconducting state of a carrier-doped topological insulator. Based on the quasi-classical approximation, we obtain an analytical expression of the energy dispersion of surface Andreev bound states (ABSs) and a compact formula for tunneling conductance of normal metal/STI junctions. The obtained compact formula of tunneling conductance makes the analysis of experimental data easy. As an application of our theory, we study tunneling conductance in Cu$_x$Bi$_2$Se$_3$. We reveal that our theory reproduces the previous results by Yamakage {\it et al} [Phys. Rev. B 85, 180509(R) (2012)]. We further study magneto-tunneling spectroscopy in the presence of external magnetic fields, where the energy of quasiparticles is shifted by the Doppler effect. By rotating magnetic fields in the basal plane, we can distinguish between two different topological superconducting states with and without point nodes, in their magneto-tunneling spectra.

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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