Interplay between spin–orbit coupling and crystal-field effect in topological insulators. (30th June 2015)

• Record Type: Journal Article
• Authors: Lee, Hyungjun; Yazyev, Oleg V
• Is Part Of: Journal of physics. Volume 27:Number 28(2015)
• Publication Date: 2015-06-30
• Subjects: topological insulator -- spin–orbit interaction -- crystal field effect -- first-principles calculations; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/0953-8984/27/28/285801
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Band inversion, one of the key signatures of time-reversal invariant topological insulators (TIs), arises mostly due to the spin–orbit (SO) coupling. Here, based on ab initio density-functional calculations, we report a theoretical investigation of the SO-driven band inversion in isostructural bismuth and antimony chalcogenide TIs from the viewpoint of its interplay with the crystal-field effect. We calculate the SO-induced energy shift of states in the top valence and bottom conduction manifolds and reproduce this behavior using a simple one-atom model adjusted to incorporate the crystal-field effect. The crystal-field splitting is shown to compete with the SO coupling, that is, stronger crystal-field splitting leads to weaker SO band shift. We further show how both these effects can be controlled by changing the chemical composition, whereas the crystal-field splitting can be tuned by means of uniaxial strain. These results provide a practical guidance to the rational design of novel TIs as well as to controlling the properties of existing materials.