Nanoscale interplay of strain and doping in a high-temperature superconductor

TL;DR

This study reveals how nanoscale variations in strain and doping are interconnected in a high-temperature superconductor, providing insights that could inform future enhancements of superconducting properties.

Contribution

It uncovers the periodic distribution of oxygen dopants and their correlation with local strain in a cuprate superconductor using advanced microscopy techniques.

Findings

Oxygen dopants are periodically distributed in the material.

Dopants are correlated with local strain variations.

Structural data supports microscopic theoretical models.

Abstract

The highest temperature superconductors are electronically inhomogeneous at the nanoscale, suggesting the existence of a local variable which could be harnessed to enhance the superconducting pairing. Here we report the relationship between local doping and local strain in the cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$. We use scanning tunneling microscopy to discover that the crucial oxygen dopants are periodically distributed, in correlation with local strain. Our picoscale investigation of the intra-unit-cell positions of all oxygen dopants provides essential structural input for a complete microscopic theory.