Electronic g-factor and tunable spin-orbit coupling in a gate-defined InSbAs quantum dot

Abstract

We investigate transport properties of stable gate-defined quantum dots formed in an InSb${}_{0.87}$As${}_{0.13}$ quantum well. High $\text{g}$-factor and strong spin-orbit-coupling make InSb${}_x$As${}_{1-x}$ a promising platform for exploration of topological superconductivity and spin-based devices. We extract a nearly isotropic in-plane effective $\text{g}$-factor by studying the evolution of Coulomb blockade peaks and differential conductance as a function of the magnitude and direction of magnetic field. The in-plane $\text{g}$-factors, $|g_{[1\bar{1}0]}^{\ast }|$ and $|g_{[110]}^{\ast }|$, range from 49 - 58. Interestingly, this $\text{g}$-factor is higher than that found in quantum dots fabricated from pure InSb quantum wells. We demonstrate tunable spin-orbit-coupling by tracking a spin-orbit-coupling mediated avoided level crossing between the ground state and an excited state in magnetic field. By increasing the electron density, we observed an increase in an avoided crossing separation, ${\Delta }_{SO}$. The maximum energy separation extracted is ${\Delta }_{SO}$$\sim$100 $\mu$eV.