Quantum-dot lithium in strong-interaction regime: Depolarization of electron spins by magnetic field

Magnetic field usually leads to a polarization of electron spins. It is shown that in a system of {\em strongly interacting} particles applying magnetic field may lead to an opposite effect -- depolarization of electron spins. Results of the work are based on an exact-diagonalization study of quantum-dot lithium -- a system of three Coulomb interacting two-dimensional electrons in a parabolic confinement potential.