THz detection by multi-layered topological insulator

We propose electrical THz detection based on topological insulators which have Dirac electrons. Among them, multi-layered topological insulator system is expected to stack topological interface states and hence enhancement of photo absorption is likely to be realized. GeTe/Sb
₂
Te
₃
interfacial phase change memory materials (iPCM) were used and THz-induced electrical response was measured. As a result, we found that the irradiation of THz pulse causes decrease in the resistance of the device. It was found that the sensitivity of the device can be enhanced by increase of repetition number of iPCM due to the multiplication of topological states.