Self-interaction corrected band structure of black-phase SmS

R. Schumann^{a , *}, A. Mishchenko^b and M. Richter <sup>c

a</sup> TU Dresden, Institut für Theoretische Physik, Dresden, Germany
^b Kurchatov-Institute, Moscow, Russian Federation
^c TU Dresden, Max-Planck-Forschungsgruppe, Elektronische Systeme Dresden, Germany

Abstract

We extend a local density (LDA) calculation with self-interaction corrections (SIC) applied to black-phase SmS with six 4f-states assumed localized to the case where the valency of the Sm ion becomes a non-integer. We propose the construction of localized molecular orbital (MO) states of correct symmetry by superposition of 4f states with a linear combination of 5d states at the adjacent atoms. These orbitals are more extended than pure 4f-states and, therefore, yield a smaller SIC in dependence of the 5d weight. Simultaneously, this parameter determines the 4f occupancy. Our self-consistent SIC-LDA calculation shows that the correlation between the MO level position and the 4f occupancy is consistent with experiment if only one of the six 4f states is treated in this way. If the MO level reaches the bottom of the conduction band a reconstruction of the electronic structure should take place.

Author Keywords: SmS; Intermediate valence; Electronic band structure; Self-interaction correction

^*Corresponding author.