The electronic structure of UCoGe by ab initio calculations and XPS experiment

Abstract

The crystal and electronic structures of the orthorhombic compound UCoGeare presented and discussed. It has been either refined by the x-ray diffractionon a single crystal or computed within the local spin density functional theory,employing the fully relativistic version of the full-potential local-orbital band structurecode, respectively. We particularly give our attention to investigating the Fermisurface and de Haas–van Alphen quantities of UCoGe. The calculated electronicdensity is then examined by x-ray photoelectron spectroscopy (XPS). Fairly goodagreement is achieved between theoretical and experimental XPS results in theparamagnetic state. A small difference in the position (in energy scale) of the U 5fbands is caused by the electron localization effect observed in the experimentalXPS. There is also some discrepancy for the Co 3d electron contributions belowEF. The Fermi surface in the non-magnetic state is of a semimetallic typewhile that in the ferromagnetic state, with the ordered moment of−0.47 μB/f.u. alongthe c axis, is more metallic, with nesting properties that may favour superconductivity.