Manipulation of the Land$\acute{\text{e}}$ g-factor in InAs quantum dots through the application of anisotropic gate potentials: Exact diagonalization, numerical and perturbation methods

TL;DR

This paper investigates how anisotropic gate potentials and magnetic fields influence the Landé g-factor in InAs quantum dots, revealing electric field tunability and the effects of Rashba spin-orbit coupling for quantum computing applications.

Contribution

It provides analytical and numerical analysis of g-factor variation due to anisotropic potentials and spin-orbit interactions, highlighting the impact of electric fields and anisotropy on quantum dot spin properties.

Findings

Electric fields can tune the g-factor over a wide range.

Anisotropic potentials reduce g-factor variation through orbital angular momentum quenching.

Level crossings and anticrossings of electron states are identified and modeled.

Abstract

We study the variation in the Land$\acute{\text{e}}$ g-factor of electron spins induced by both anisotropic gate potentials and magnetic fields in InAs quantum dots for possible implementation towards solid state quantum computing. In this paper, we present analytical expressions and numerical simulations of the variation in the Land$\acute{\text{e}}$ g-factor for both isotropic and anisotropic quantum dots. Using both analytical techniques and numerical simulations, we show that the Rashba spin-orbit coupling has a major contribution in the variation of the g-factor with electric fields before the regime, where level crossing or anticrossing occurs. In particular, the electric field tunability is shown to cover a wide range of g-factor through strong Rashba spin-orbit interaction. Another major result of this paper is that the anisotropic gate potential gives quenching effect in the orbital angular momentum that reduces the variation in the E-field and B-field tunability of the g-factor if the area of the symmetric and asymmetric quantum dots is held constant. We identify level crossings and anticrossings of the electron states in the variation of the Land$\acute{\text{e}}$ g-factor. We model the wavefunctions of electron spins and estimate the size of the anticrossing for the spin states $|0,-1,+1/2>$ and $|0,0,-1/2>$ corresponding to a quantum dot that has been recently studied experimentally (Phys. Rev. Lett. \textbf{104}, 246801 (2010)).