The superconducting proximity effect in Bi2Se3 thin-films.

摘要

States of matter distinguished by the topology of their bands rather than any broken symmetry represent a vast, largely unexplored realm of condensed matter physics. Such states, realized in condensed matter systems, support exotic excitations that obey rules distinct from fermions and bosons. They are of basic interest, illustrating Nature's limitless creativity, and practical interest in that they may prove ideal platforms for the construction of error-proof quantum computational devices. In this work, the topological insulator Bi2Se3, which supports special metallic surface states as a consequence of the topology of its bulk bands, is tiled with micron-scale islands of the superconductor niobium. The superconducting islands interact with the Bi2Se3 and each other through the superconducting proximity effect and the Josephson effect. Theoretical work asserts that this system supports so-called Majorana bound states, which are exotic excitations that possess some of the features necessary to construct a topologically protected quantum bit. Transport studies on these topological Josephson array devices show that the presence of the islands leads to correlated transport and vortex dynamics in the topological insulator wire. These devices may serve as an ideal platform for further investigation into Majorana physics and other manifestations of the topological nature of the Bi2Se3 wires.