Electronic nematic normal and superconducting state in electron-doped copper-oxide superconductors

TL;DR

This study reveals intrinsic electronic nematicity in the normal and superconducting states of electron-doped cuprate Sr0.9La0.1CuO2, highlighting its role in high-temperature superconductivity and its dependence on electron-electron interactions.

Contribution

It provides direct evidence of electronic nematicity in electron-doped cuprates and shows how strain and doping influence its amplitude and origin.

Findings

Nematicity exists in the normal state of electron-doped Sr0.9La0.1CuO2.

Nematicity is enhanced by superconducting fluctuations and lower doping.

Nematicity originates from electron-electron correlations.

Abstract

The similarities and differences between hole- and electron-doped cuprates are central to studies of high-temperature superconductivity. While electronic nematicity is found to be pervasive in hole-doped cuprates, iron-based superconductors, and other unconventional superconductors, evidence for electronic nematicity in electron-doped cuprates remains elusive. Here, we discover that the normal state of electron-doped Sr0.9La0.1CuO2 (SLCO) is nematic by the angle-resolved resistivity (ARR) method and the uncovered ground state at zero temperature is also nematic when superconductivity is suppressed by an applied magnetic field. As we deliberately change the substrate from tetragonal KTaO3(001) (KTO) to orthorhombic GdScO3(110) (GSO), the nematic director of SLCO is pinned by the epitaxial strain but the nematic amplitude remains roughly the same, implying that the nematicity originates from electron-electron correlations. The nematicity is significantly enhanced by the presence of superconducting fluctuations and its amplitude increases appreciably as the effective doping level of SLCO is lowered from optimal to underdoped. Thus, electronic nematicity is intrinsic to high-temperature superconductors regardless of differences in the structural and electronic configurations corresponding to hole or electron doping.