THz Photodetector using sideband-modulated transport through surface states of a 3D Topological Insulator

TL;DR

This paper proposes a theoretical THz photodetector based on surface states of a 3D topological insulator, utilizing sideband-modulated transport influenced by a resonant double barrier structure and Floquet theory.

Contribution

It introduces a novel theoretical approach for THz detection using surface state transport modulation in topological insulators, analyzing the effects of scattering and resonances.

Findings

Sidebands in conductance spectrum enable THz frequency detection

Elastic and inelastic scattering influence transmission sidebands

Bias voltage and zero energy points affect device response

Abstract

The transport properties of the surface charge carriers of a three dimensional topological insulator under a terahertz (THz) field along with a resonant double barrier structure is theoretically analyzed within the framework of Floquet theory to explore the possibility of using such a device for photodetection purpose. We show that due to the contribution of elastic and inelastic scattering processes in the resulting transmission sidebands are formed in the conductance spectrum in somewhat similar way as in an optical cavity and this information can be used to detect the frequency of an unknown THz radiation. The dependence of the conductance on the bias voltage, the effect of THz radiation on resonances and the influence of zero energy points on the transmission spectrum are also discussed.