Eur. Phys. J. B (2013) 86: 481
https://doi.org/10.1140/epjb/e2013-40812-9

Regular Article

Bound-states and polarized charged zero modes in three-dimensional topological insulators induced by a magnetic vortex

¹ Grupo de Física/ICET/CRP, Universidade Federal de Viçosa, Rodovia MG-230 Km 7, Cep 38810-000, Rio Paranaíba, Minas Gerais, Brazil
² Departamento de Física, Universidade Federal de Viçosa, Viçosa, Cep 36570-000, Minas Gerais, Brazil

^a e-mail: jakson.fonseca@ufv.br

Received: 3 September 2013
Received in final form: 9 October 2013
Published online: 20 November 2013

Abstract

By coating a three-dimensional topological insulator (TI) with a ferromagnetic film supporting an in-plane magnetic vortex, one breaks the time-reversal symmetry (TRS) without generating a mass gap. It rather yields electronic states bound to the vortex center which have different probabilities associated with each spin mode. In addition, its associate current (around the vortex center) is partially polarized with an energy gap separating the most excited bound state from the scattered ones. Charged zero-modes also appear as fully polarized modes localized near the vortex center. From the magnetic point of view, the observation of such a special current in a TI-magnet sandwich comes about as an alternative technique for detecting magnetic vortices in magnetic thin films.