Electron and magnetic properties of three-dimensional magnetic topological insulators Bi₂Se₃:Cr and Bi₂Se₃:Fe

¹ Prokhorov General Physics Institute, Russian Academy of Sciences - 119991 Vavilov str. 38, Moscow, Russia
² National Research Center Kurchatov Institute - 123182, Kurchatov Sqr. 1, Moscow, Russia
³ Tomsk State University - 634050, pr. Lenina 36, Tomsk, Russia
⁴ P.N. Lebedev Physical Institute, Russian Academy of Sciences - 119991 Leninskii prosp. 53, Moscow, Russia

^(a) kulatov@td.lpi.ru

Received: 16 August 2016
Accepted: 7 October 2016

Abstract

This letter presents the first-principles study of a three-dimensional (3D) topological insulator (TI) Bi₂Se₃ doped with magnetic atoms of 3d-transition metal (TM), Cr or Fe. Calculations are performed within the density functional theory (DFT) and a modified potential of Becke and Johnson (MBJ). Using the MBJ scheme, we show that both systems are semiconductors with a direct gap of 0.21 eV (Bi₂Se₃:Cr) and 0.27 eV (Bi₂Se₃:Fe), respectively. The magnetic structures of studied materials are, however, different: Bi₂Se₃:Cr exhibits a clear ferromagnetic (FM) order, while Bi₂Se₃:Fe has an antiferromagnetic (AFM) order. In view of the great scientific and practical interest to the 3D FMTI systems, the optical and magneto-optical spectra of Bi₂Se₃:Cr are calculated.