Spin-orbit effects on two-electron states in nanowhisker double quantum dots

TL;DR

This paper theoretically examines how electron-electron and Rashba spin-orbit interactions influence two-electron states in nanowhisker double quantum dots, revealing controllable energy level crossings and spin dynamics.

Contribution

It introduces a detailed theoretical model of combined electron-electron and spin-orbit effects in double quantum dots, highlighting control mechanisms via interdot barrier width.

Findings

Energy spectrum shows crossings and anticrossings influenced by spin-orbit coupling.

Crossing fields can be tuned by adjusting the interdot barrier width.

Spin and energy level interactions are controllable through device parameters.

Abstract

We investigate theoretically the combined effects of the electron-electron and the Rashba spin-orbit interactions on two electrons confined in quasi-one-dimensional AlInSb-based double quantum dots. We calculate the two-electron wave functions and explore the interplay between these two interactions on the energy levels and the spin of the states. The energy spectrum as a function of an applied magnetic field shows crossings and anticrossings between triplet and singlet states, associated with level mixing induced by the spin-orbit coupling. We find that the fields at which these crossings occur can be naturally controlled by the interdot barrier width, which controls the exchange integral in the structure.