Interfacial effects of proximitizing superconductivity in topological insulators*

The proximitization of superconductivity into time-reversal invariant topological insulators, as well as their magnetic counterparts, has produced exciting observations including anomalous Fraunhofer patterns[1, 2], finite momentum pairing[3], and fractional quantized conductances[4]. Yet even as the quality of topological materials rapidly improves, variations in behavior across different experiments and groups are not well understood. We postulate that the properties of the interface between superconducting metals and topological insulators play a key role, and we discuss our attempts to characterize and manipulate such interfaces, focusing on the (BiSb)₂Te₃ family of topological insulators.

[1] Williams, J. R., et al. Phys. Rev. Lett. 109, 056803 (2012)
[2] Ghatak, S. et al. Nano Lett. 18, 5124-5131 (2018)
[3] Chen, A. Q., et al. Nature Comm. 9, 3478 (2018)
[4] He, Q. L., et al. Science 357, 294-299 (2017)