High-frequency enhanced response based on Sb2Te3 topological insulators

Abstract

Topological insulators represent a new quantum phase of matter with spin-polarized surface states that are protected from backscattering, exhibiting electronic responses to light, such as topological quantum phase transitions. However, the effects of high-frequency driving topological intrinsic systems have remained largely unexplored challenges experimentally for high-sensitivity terahertz detection. In this study, by integrating Sb 2 Te 3 topological insulators with subwavelength metal antennas through micro-nano processing, a high-frequency terahertz detector with high sensitivity is proposed. The enhanced response originates from the asymmetric scattering of the surface electrons in the Sb 2 Te 3 flakes induced by the terahertz wave. The device displays room-temperature photodetection with a responsivity of 192 mA/W and equivalent noise power of less than 0.35 nW / Hz 1 / 2 in the frequency range from 0.02 to 0.3 THz. These results pave the way for the exploitation of topological insulators for high-frequency operation in real-time imaging within long-wavelength optoelectronics.