Quantum Oscillations in Ferromagnetic (Sb, V)2Te3 Topological Insulator Thin Films

An effective way of manipulating 2D surface states in magnetic topological insulators may open a new route for quantum technologies based on the quantum anomalous Hall effect. The doping-dependent evolution of the electronic band structure in the topological insulator Sb2-xVxTe3 (0 <= x <= 0.102) thin films is studied by means of electrical transport. Sb2-xVxTe3 thin films were prepared by molecular beam epitaxy, and Shubnikov-de Hass (SdH) oscillations are observed in both the longitudinal and transverse transport channels. Doping with the 3d element, vanadium, induces long-range ferromagnetic order with enhanced SdH oscillation amplitudes. The doping effect is systematically studied in various films depending on thickness and bottom gate voltage. The angle-dependence of the SdH oscillations reveals their 2D nature, linking them to topological surface states as their origin. Furthermore, it is shown that vanadium doping can efficiently modify the band structure. The tunability by doping and the coexistence of the surface states with ferromagnetism render Sb2-xVxTe3 thin films a promising platform for energy band engineering. In this way, topological quantum states may be manipulated to crossover from quantum Hall effect to quantum anomalous Hall effect, which opens an alternative route for the design of quantum electronics and spintronics.

Automated summary

The study demonstrates that doping with vanadium can effectively modify the band structure in magnetic topological insulators, leading to the enhancement of SdH oscillations and the induction of long-range ferromagnetic order. The angle-dependent SdH oscillations reveal their 2D nature and their connection to topological surface states. This tunability by doping and the coexistence of surface states with ferromagnetism highlight the potential of Sb2-xVxTe3 thin films in energy band engineering for quantum electronics and spintronics design.