Gigantic anisotropic uniaxial pressure effect on superconductivity within the CuO2 plane of La1.64Eu0.2Sr0.16CuO4 - strain control of stripe criticality

TL;DR

This study reveals a gigantic anisotropic uniaxial pressure effect on superconductivity in La1.64Eu0.2Sr0.16CuO4, highlighting strain's role in stripe criticality and phase boundary control.

Contribution

It demonstrates the largest in-plane uniaxial pressure effect on Tc in cuprates and links strain symmetry to stripe order within the CuO2 plane.

Findings

Uniaxial pressure along [110] greatly increases Tc by 2.5 K/kbar.

In-plane pressure effects are highly anisotropic, minimal along [100].

Strain symmetry is closely related to stripe order and superconductivity.

Abstract

The effect of uniaxial pressure on superconductivity was examined for a high-Tc cuprate La1.64Eu0.2Sr0.16CuO4, which is located at the boundary between the superconducting and stripe phases. We found remarkably large anisotropy of the uniaxial pressure effect not only between the in-plane and out-of-plane pressures but also within the CuO2-plane. When the pressure is applied along the tetragonal [110] direction, we found the largest pressure effect ever observed in cuprates, dTc/dP - 2.5 K/kbar, while the change of Tc was not appreciable when applied along [100]. This substantial in-plane anisotropy is attributed to an intimate link between the symmetry of the one-dimensional stripes and that of the strain produced within the CuO2 plane.