Impurity states in the magnetic topological insulator V:(Bi,Sb)${}_2$Te${}_3$

Abstract

The ferromagnetic topological insulator V:(Bi,Sb)${}_2$Te${}_3$ has been recently reported as a quantum anomalous Hall (QAH) system. Yet the microscopic origins of the QAH effect and the ferromagnetism remain unclear. One key aspect is the contribution of the V atoms to the electronic structure. Here the valence band of V:(Bi,Sb)${}_2$Te${}_3$ thin films was probed in an element-specific way by resonant photoemission spectroscopy. The signature of the V $3d$ impurity band was extracted, and exhibits a high density of states near Fermi level. First-principles calculations support the experimental results and indicate the coexistence of ferromagnetic superexchange and double exchange interactions. The observed impurity band is thus expected to contribute to the ferromagnetism via the interplay of different mechanisms.

arXiv comment5 pages, 3 figures, figure 3 changed, new references and discussion included

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Cited by in corpus (17)

• Colloquium: Quantum anomalous Hall effect
• Quantum anomalous Hall effect driven by magnetic proximity coupling in all-telluride based heterostructure
• Systematics of electronic and magnetic properties in the transition metal doped Sb${}_2$Te${}_3$ quantum anomalous Hall platform
• Effect of Rashba splitting on RKKY interaction in topological insulator thin films
• Spectroscopic perspective on the interplay between electronic and magnetic properties of magnetically doped topological insulators
• Observation of superparamagnetism in coexistence with quantum anomalous Hall C=$\pm$1 and C=0 Chern states
• Noncollinear twisted RKKY interaction on the optically driven SnTe(001) surface
• Incipient antiferromagnetism in the Eu-doped topological insulator Bi${}_2$Te${}_3$
• Microscopic effects of Dy-doping in the topological insulator Bi2Te3
• Impurity scattering on the surface of topological insulator thin films
• Ubiquitous impact of localised impurity states on the exchange coupling mechanism in magnetic topological insulators
• The AiiDA-KKR plugin and its application to high-throughput impurity embedding into a topological insulator
• Ab initio investigation of impurity-induced in-gap states in Bi${}_2$Te${}_3$ and Bi${}_2$Se${}_3$
• Magnetization relaxation and search for the magnetic gap in bulk-insulating V-doped (Bi, Sb)${}_2$Te${}_3$
• Spontaneous ferromagnetism and finite surface energy gap in the topological insulator Bi${}_2$Se${}_3$ from surface Bi$_\rm{Se}$ antisite defects
• Revisiting magnetic exchange interactions in transition metal doped Bi${}_2$Se${}_3$ using DFT+MFT
• Magnetic interactions of 4$f$ electrons in the topological insulator chalcogenide Bi${}_2$Se${}_3$