Enhanced critical temperatures in the strongly overdoped iron-based superconductors AFe$_2$As$_2$ (A = K, Cs, Rb) observed by point contacts

TL;DR

This study reports a significant increase in the superconducting critical temperature in point contacts on iron-based superconductors, likely due to interfacial effects such as doping or pressure, revealing potential for enhancing superconductivity.

Contribution

The paper presents experimental evidence of Tc enhancement in point contacts on AFe$_2$As$_2$ superconductors and discusses possible interfacial mechanisms behind this phenomenon.

Findings

Tc increased by up to 10 K in point contacts

Interfacial doping and pressure likely cause Tc enhancement

Potential for tuning superconductivity via contact engineering

Abstract

A remarkable several times increase (up to 10 K) of the superconducting critical temperature Tc has been observed in point contacts created on the base of single crystals AFe$_2$As$_2$ (A = K, Cs, Rb). Possible reasons for such a Tc increase in point contacts are briefly discussed on a qualitative level. Among them, it is most likely attributed to interfacial carrier doping and/or uniaxial non-homogeneous pressure arising when the contact is created.