Strain engineering of photoinduced anomalous Hall effect in topological insulator Sb2Te3

Abstract

The photoinduced anomalous Hall effect (PAHE) serves as a powerful probe for investigating topological band structures in quantum materials. While three-dimensional (3D) topological insulators (TIs) like Sb2Te3 exhibit promising spintronic properties, achieving effective modulation of their PAHE remains experimentally challenging. This study demonstrates strain-engineered control of PAHE in Sb2Te3 thin films with thicknesses ranging from 5 to 20 quintuple layers (QLs). Through systematic strain-dependent measurements, we reveal a non-monotonic thickness-mediated response: the PAHE current initially increases then decreases under uniaxial tensile strain across all studied thicknesses. Remarkably, the seven QL sample under 0.18% tensile strain exhibits a record-high photoinduced anomalous Hall conductivity of 1.88×103 m/(Ω· W) under 1064 nm illumination. Comprehensive analysis of strain-dependent sheet resistance (Rs), photoconductivity current (IPC) of the Si substrates, and circular photogalvanic effect (CPGE) current of the Sb2Te3 films on Si substrates, uncovers a strain-mediated mechanism governed by the synergistic effects of spin injection from Si substrates and strain-modulated spin–orbit coupling strength. Our findings demonstrate a viable strategy for manipulating quantum transport through strain engineering while providing insights into the interplay between mechanical deformation and topological electronic states.