A Study of Electronic Nematicity in Cuprate Superconductors using Resonant Soft X-Ray Scattering

Abstract

The cuprate high-temperature superconductors involve a complex interplay between different structural and electronic symmetry-breaking phases. In the last decade, rotational and translational symmetry-breaking phases — electronic nematicity and density wave order — have been established as generic and distinct features in the cuprate phase diagram using different probes. To understand this connection between these symmetry breaking phases, we use resonant soft x-ray scattering (RSXS) — a technique that combines x-ray diffraction and x-ray absorption spectroscopy — at different photon energies allowing us to differentiate between ionic displacement and orbital asymmetry. The results presented in this thesis are based on the measurements performed at the REIXS beamline at the Canadian Light Source in Saskatoon, Canada. In this thesis, we employ RSXS to explore the low-energy physics of different symmetry breaking phases in a Lanthanum-based cuprate high-temperature superconductor as a function of hole doping. The scattering cross-section on resonance develops sensitivity to the orbital symmetry which at different photon energies can be used to probe the relationship between electronic nematicity of the copper-oxide planes, structural distortions, and charge density wave order.