Qdev seminar by Karina Hudson, UNSW Sydney

Detection and design for spin-orbit interaction: orientation dependent g-factors arising from lattice anisotropy in GaAs spin-3/2 hole quantum point contacts

Many modern spin-based devices rely on the spin-orbit interaction, which is highly sensitive to the host semiconductor and depends on the crystal orientation, crystal asymmetry, and quantum confinement asymmetry.

One-dimensional quantum point contacts are a powerful tool to probe both energy and orientation dependence of the spin-orbit interaction through the effect on the hole g-factor.

I will present recent results demonstrating the role of cubic crystal asymmetry in GaAs when the quantum point contact is rotated with respect to the crystal axes.

We find the in-plane g-factors to be extremely sensitive to the point contact orientation and present new theoretical modelling based on the combined Luttinger, Rashba and Dresselhaus Hamiltonians reveals new spin-orbit contributions to the in-plane hole g-factor and provides excellent agreement with experimental data.

These results show that device orientation with respect to cubic crystal substrate is a critical design consideration for devices that rely on spin-orbit interaction.