Electrical and terahertz magnetospectroscopy studies of laser-patterned micro- and nanostructures on InAs-based heterostructures

Abstract

Nanostructures fabricated from narrow-gap semiconductors with strong spin-orbit interaction (SOI), such as InAs, can be used to filter momentum modes of electrons and offer the possibility to create and detect spin-polarized currents entirely by electric fields. Here, we present magnetotransport and THz magnetospectroscopy investigations of Hall-bars with back-gates made from in InGaAs/InAlAs quantum well structures with a strained 4 nm InAs inserted channel. The two-dimensional electron gas is at 53 nm depth and has a carrier density of about $6\times10^{11}$ cm$^{-2}$ and mobility of about $2\times10^{5}$ cm$^2$/Vs, after illumination. Electrical and THz optical transport measurements at low temperatures and in high magnetic fields reveal an effective mass of 0.038$m_{0}$ and an anisotropic $g$-factor of up to 20, larger than for bulk InAs or InAs-based heterostructures. We demonstrate that quasi-one-dimensional channels can be formed by micro-laser lithography. The population of subbands is controlled by in-plane gates. Contrary to previous reports symmetric and asymmetric in-plane gate voltages applied to quasi-one dimensional channels did not show indications of SOI-induced anomalies in the conductance.