Abstract
We have investigated magnetic coupling between semiconductor quantum dots. The antiferromagnetization process based on the interdot exchange interaction has been directly observed using time-resolved spin-dependent photoluminescence measurements. The antiferromagnetic order that proves the interdot exchange interaction energy to be negative is found to exist at temperatures lower than 50-80 K. The spin relaxation time under the antiferromagnetic order is extended to 10-12 ns, an order of magnitude longer than that in isolated quantum dots.
