Electric-field induced spin accumulation in the Landau level states of topological insulator thin films. (21st July 2017)

• Record Type: Journal Article
• Authors: Siu, Zhuo Bin; Chowdhury, Debashree; Basu, Banasri; Jalil, Mansoor B A
• Is Part Of: Journal of physics. Volume 50:Number 32(2017)
• Publication Date: 2017-07-21
• Subjects: topological insulator -- spin accumulation -- Landau levels; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/aa77a1
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: A topological insulator (TI) thin film differs from the more typically studied thick TI system in that the former has both a top and a bottom surface where the states localized at both surfaces can couple to one other across the finite thickness. An out-of-plane magnetic field leads to the formation of discrete Landau level states in the system, whereas an in-plane magnetization breaks the angular momentum symmetry of the system. In this work, we study the spin accumulation induced by the application of an in-plane electric field to the TI thin film system where the Landau level states and inter-surface coupling are simultaneously present. We show, via Kubo formula calculations, that the in-plane spin accumulation perpendicular to the magnetization due to the electric field vanishes for a TI thin film with symmetric top and bottom surfaces. A finite in-plane spin accumulation perpendicular to both the electric field and magnetization emerges upon applying either a differential magnetization coupling or a potential difference between the two film surfaces. This spin accumulation results from the breaking of the antisymmetry of the spin accumulation around the k -space equal-energy contours.