Eur. Phys. J. B (2016) 89: 5
https://doi.org/10.1140/epjb/e2015-60753-5

Regular Article

Electronic structure of CeRu₄Sn₆: a density functional plus dynamical mean field theory study

Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria

^a e-mail: held@ifp.tuwien.ac.at

Received: 18 September 2015
Received in final form: 13 November 2015
Published online: 11 January 2016

Abstract

The Kondo system CeRu₄Sn₆ shows a strong anisotropy in its electric, optic and magnetic properties. We employ density functional theory plus dynamical mean field theory and show that the predominant Ce-f state has total angular moment J = 5 / 2 and z-component m_J = ± 1 / 2 in agreement with recent X-ray absorption experiments. There is also an admixture of m_J = ± 3 / 2 which is reduced in favor of m_J = ± 1 / 2 with the onset of the Kondo effect. Even though CeRu₄Sn₆ has the direct gap of a Kondo insulator through most of the Brillouin zone it remains weakly metallic. This is because of (i) a band crossing in the z-direction and (ii) a negative indirect gap.