Reinforcement of interfacial superconductivity in a Bi2Te3/Fe1+yTe heterostructure under hydrostatic pressure

TL;DR

This study shows that applying hydrostatic pressure enhances interfacial superconductivity in a Bi2Te3/Fe1+yTe heterostructure, with increased transition temperature and superconducting gaps, highlighting the TI's role in the mechanism.

Contribution

It reveals how hydrostatic pressure induces doping at the interface, significantly boosting interfacial superconductivity in a topological insulator/iron chalcogenide heterostructure.

Findings

Superconducting transition temperature Tc increases with pressure.

Large superconducting gap associated with interfacial superconductivity grows under pressure.

Proximity-induced superconductivity in the TI layer initially increases then diminishes at higher pressure.

Abstract

We investigate the hydrostatic pressure dependence of interfacial superconductivity occurring at the atomically sharp interface between two non-superconducting materials: the topological insulator (TI) Bi2Te3 and the parent compound Fe1+yTe of the chalcogenide iron based superconductors. Under pressure, a significant increase in the superconducting transition temperature Tc is observed. We trace the pressure dependence of a superconducting twin gap structure by Andreev reflection point contact spectroscopy (PCARS), which shows that a large superconducting gap associated with the interfacial superconductivity increases along with Tc. A second smaller gap, which is attributed to proximity-induced superconductivity in the TI layer, increases first, but then reaches a maximum and appears to be gradually suppressed at higher pressure. We interpret our data in the context of a pressure-induced doping effect of the interface, in which charge is transferred from the TI layer to the interface and the interfacial superconductivity is enhanced. This demonstrates the important role of the TI in the interfacial superconductivity mechanism.