Interplay between electron spin and orbital pseudospin in double quantum dots

TL;DR

This paper theoretically explores how electron spin and orbital pseudospin interact in double quantum dots, revealing different coupling behaviors depending on dot shape and electron filling, and proposes an experiment to test these effects.

Contribution

It provides a detailed theoretical analysis of spin and pseudospin interactions in double quantum dots, including effects of dot shape and electron number, with new insights into their coupling mechanisms.

Findings

Spins in different dots are ferromagnetically coupled in parabolic DQDs.

Orbital pseudospins are antiferromagnetically coupled in parabolic DQDs.

Coupling depends on electron number and dot shape in elliptic DQDs.

Abstract

We investigate theoretically spin and orbital pseudospin magnetic properties of a molecular orbital in parabolic and elliptic double quantum dots (DQDs). In our many body calculation we include intra- and inter-dot electron-electron interactions, in addition to the intradot exchange interaction of `p' orbitals. We find for parabolic DQDs that, except for the half or completely filled molecular orbital, spins in different dots are ferromagnetically coupled while orbital pseudospins are antiferromagnetically coupled. For elliptic DQDs spins and pseudospins are either ferromagnetically or antiferromagnetically coupled, depending on the number of electrons in the molecular orbital. We have determined orbital pseudospin quantum numbers for the groundstates of elliptic DQDs. An experiment is suggested to test the interplay between orbital pseudospin and spin magnetism.