Interplay between Mn-acceptor state and Dirac surface states in Mn-doped Bi${}_2$Se${}_3$ topological insulator

Abstract

We investigate the properties of a single substitutional Mn impurity and its associated acceptor state on the (111) surface of Bi${}_2$Se${}_3$ topological insulator. Combining ab initio calculations with microscopic tight-binding modeling, we identify the effects of inversion-symmetry and time-reversal-symmetry breaking on the electronic states in the vicinity of the Dirac point. In agreement with experiments, we find evidence that the Mn ion is in the $+2$-valence state and introduces an acceptor in the bulk band gap. The Mn-acceptor has predominantly $p$-character, and is localized mainly around the Mn impurity and its nearest-neighbor Se atoms. Its electronic structure and spin-polarization are determined by the hybridization between the Mn $d$-levels and the $p$-levels of surrounding Se atoms, which is strongly affected by electronic correlations at the Mn site. The opening of the gap at the Dirac point depends crucially on the quasi-resonant coupling and the strong real-space overlap between the spin-chiral surface states and the mid-gap spin-polarized Mn-acceptor states.

5 pages, 5 figures, journal

References in corpus (6)

• Topological Field Theory of Time-Reversal Invariant Insulators
• Quantized Anomalous Hall Effect in Magnetic Topological Insulators
• The development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3
• Ordering of magnetic impurities and tunable electronic properties of topological insulators
• Tailoring Magnetic Doping in the Topological Insulator Bi2Se3
• Infrared electrodynamics and ferromagnetism in the topological semiconductors Bi${}_2$Te${}_3$ and Mn-doped Bi${}_2$Te${}_3$

Cited by in corpus (1)

• Impurity-potential-induced gap at the Dirac point of topological insulators with in-plane magnetization