Spin-orbit sensitive hard x-ray probe of the occupied and unoccupied5ddensity of states

Abstract

We discuss a truly bulk sensitive, $j$-selective probe of the valence and conduction bands of the $5d$ transition metal systems. The electronic structure of Re and W oxides, with formal occupation of $d$-states ranging from $5d$${}^{0}$ to $5d$${}^{3}$, was investigated by means of resonant x-ray emission spectroscopy (RXES) across the L${}_{3}$ and L${}_{2}$ edges of Re (\ensuremath{\sim}10.5 and \ensuremath{\sim}12 keV, respectively) and W (\ensuremath{\sim}10 and \ensuremath{\sim}11.5 keV, respectively). We present a systematic theoretical analysis of the RXES spectra within a density functional theory band structure approach. Excellent agreement between experiment and theory is achieved, demonstrating that the theory accounts for the most relevant interactions within the experimental energy bandwidth (\ensuremath{\sim}2--3 eV). Differences between the L${}_{3}$ and the L${}_{2}$ edges can be reproduced by considering spin-orbit interaction. The possible applications and limitations of our approach are discussed.