High pressure XAS studies of local atomic and electronic properties in La3Ni2O7 high-Tc superconductor

A very recent breakthrough in superconductivity research has led to the discovery of high temperature (high-Tc) superconductivity with a maximum of Tc of 80 K in La3Ni2O7 single crystals under high pressure. This discovery marked the first experimental evidence of superconductivity in the Ruddlesden-Popper phase nickelates, making La3Ni2O7 the second system after cuprates to exhibit superconductivity at temperatures above the boiling point of nitrogen (except hydrates that show high-Tc at ultra-high pressures). However, many basic properties of this compound need to be systematically studied under high pressure and low temperature to understand the origin of its conductivity. Here, we propose to perform Ni K-edge XAS investigations to understand the evolution of local atomic (e.g., Ni-O, Ni-Ni interactions) and electronic properties (e.g., valence, 3d orbital configurations) of La3Ni2O7, across its superconducting transition.