Electronic State of T'-Pr$_{1.3-x}$La$_{0.7}$Ce$_x$CuO$_4$ ($x = 0.10$) Studied by Compton Scattering

TL;DR

This study uses Compton scattering to examine how reduction annealing affects the electronic states in electron-doped T'-cuprate Pr1.3-xLa0.7CexCuO4, revealing increased electron populations and evidence of local hole doping.

Contribution

First spectroscopic evidence showing reduction annealing increases electron populations in specific orbitals and induces local hole doping in T'-cuprate superconductors.

Findings

Electrons in O2p, Cu3dx2-y2, and Cu3d3z2-r2 orbitals increase after reduction.

Reduction annealing suggests hole doping in Cu3d3z2-r2 orbital.

Spectroscopic evidence supports previous transport measurement hypotheses.

Abstract

We have performed Compton scattering measurements on as-grown and reduced single crystals of the electron-doped T'-cuprate Pr1.3-xLa0.7CexCuO4 (x = 0.10) to investigate the effect of reduction annealing on the electronic state. The obtained results have revealed that the numbers of electrons in the O2p orbital in the Zhang-Rice singlet band, the Cu3dx2-y2 orbital, and the Cu3d3z2-r2 orbital are increased by reduction annealing. The increase in the number of Cu3d3z2-r2 electrons suggests the existence of Cu3d3z2-r2 holes in the as-grown single crystal. This is spectroscopic evidence of local hole doping into the Cu3d3z2-r2 orbital around the excess oxygen, as suggested by transport measurements [T. Adachi et al., J. Phys. Soc. Jpn. 82, 063713 (2013)].