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.

5 pages, 3 figures, figure 3 changed, new references and discussion included

References in corpus (5)

• Quantized Anomalous Hall Effect in Magnetic Topological Insulators
• High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulator
• Tailoring Magnetic Doping in the Topological Insulator Bi2Se3
• Origin of ferromagnetic response in diluted magnetic semiconductors and oxides
• Experimental Verification of Van Vleck Nature of Long-Range Ferromagnetic Order in Vanadium-Doped Three-Dimensional Topological Insulator Sb${}_2$Te${}_3$

Cited by in corpus (8)

• Colloquium: Quantum anomalous Hall effect
• 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$
• Magnetization relaxation and search for the magnetic gap in bulk-insulating V-doped (Bi, Sb)${}_2$Te${}_3$
• 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${}_3$