University of Jyv?skyl?, Physics Department, PO Box 35, 40351 Jyv?skyl?, Finland, FI
Abstract:
We study the magnetic coupling in artificial molecules composed of two and four laterally coupled quantum dots. The electronic
ground-state configurations of such systems are determined by applying current spin density functional theory which allows
to include effects of magnetic fields. While the ground-state of a two-dot molecule with strong enough inter-dot coupling
tends to be antiferromagnetic with respect to the spins of the single dot components, we find that a square lattice of four
dots has a ferromagnetic ground state.
Received 17 February 1999 and Received in final form 1 June 1999