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arXiv · 1303.5598

Anomalous Cooper pair interference on Bi2Te3 surface

Jie Shen·Yue Ding·Yuan Pang·Fan Yang·Fanming Qu·Zhongqing Ji·Xiunian Jing·Jie Fan·Guangtong Liu·Changli Yang·Genghua Chen·Li Lu
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Abstract

It is believed that the edges of a chiral p-wave superconductor host Majorana modes, relating to a mysterious type of fermions predicted seven decades ago. Much attention has been paid to search for p-wave superconductivity in solid-state systems, including recently those with strong spin-orbit coupling (SOC). However, smoking-gun experiments are still awaited. In this work, we have performed phase-sensitive measurements on particularly designed superconducting quantum interference devices constructing on the surface of topological insulators Bi2Te3, in such a way that a substantial portion of the interference loop is built on the proximity-effect-induced superconducting surface. Two types of Cooper interference patterns have been recognized at low temperatures. One is s-wave like and is contributed by a zero-phase loop inhabited in the bulk of Bi2Te3. The other, being identified to relate to the surface states, is anomalous for that there is a phase shift between the positive and negative bias current directions. The results support that the Cooper pairs on the surface of Bi2Te3 have a 2\pi Berry phase which makes the superconductivity p_x+ip_y-wave-like. Mesoscopic hybrid rings as constructed in this experiment are presumably arbitrary-phase loops good for studying topological quantum phenomena.

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Jie Shen, Yue Ding, Yuan Pang, Fan Yang, Fanming Qu, Zhongqing Ji, Xiunian Jing, Jie Fan, Guangtong Liu, Changli Yang, Genghua Chen, Li Lu. 2013-03-22. Anomalous Cooper pair interference on Bi2Te3 surface. https://arxiv.org/abs/1303.5598

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