On the role of electron exchange and correlation in semiconductor quantum dots

• Spontaneous magnetization of single and coupled quantum dots formed by lateral confinement of a high-mobility two-dimensional electron gas is studied for a realistic GaAs/AlGaAs heterostructure. The modelling of the device takes into account contributions from a patterned gate, doping, surface states, and mirror charges. To explore the magnetic properties we use the Kohn-Sham local spin-density formalism including the contributions from electron correlation and exchange. We show by explicit calculations that the exchange is the dominant mechanism driving a spontaneous magnetization of a dot. The correlation potential reduces the amount of level splitting and usually affects the electron content in the dot at a given gate voltage. These effects are, however, small and may be neglected under present circumstances. Single dots with up to 50 electrons have been studied.

Keyword

TECHNOLOGY

TEKNIKVETENSKAP

Publication and Content Type

vet (subject category)

kon (subject category)