Tuning the conductance quantization in a high spin-orbit coupling material

The control of spin-orbit fields in one-dimensional (1D) ballistic transport systems is a key element for the realization of several all-electrical concepts in the field of semiconductor spin-orbitronics. A convenient implementation of ballistic 1D transport is based on gateable two-dimensional high-mobility electron gases (2DEG). An attractive model system offering high intrinsic spin-orbit interaction is a 2DEG in InAs embedded in InAlAs/InGaAs potential walls.
In this contribution, we will discuss the design of suitable epitaxially-grown heterostructures and the electrical tuning of the conductance quantization in ballistic 1D channels. The focus of our study lies on In_0.75Al_0.25As/In_0.75Ga_0.25As quantum wells. For the realization of ballistic transport we introduce split gate defined quantum point contacts with center gates for the efficient tuning of the electric potential of the 1D constriction.