Para-ortho transition of artificial H$_2$ molecule in lateral quantum dots doped with magnetic impurities

Ramin M. Abolfath

Published 2009-07-27, updated 2009-10-27Version 2

We present the magnetic phase diagram of artificial H$_2$ molecule in lateral quantum dots doped with magnetic impurities as a function of external magnetic field and plunger gate voltage. The onset of Mn-Mn antiferromagnetic-ferromagnetic transition follows the electron spin singlet-triplet transition. We deploy a configuration-interaction method to exactly diagonalize the electron-Mn Hamiltonian and map it to an effective Mn-Mn Heisenberg Hamiltonian. We find that Mn-Mn exchange coupling can be described by RKKY-interaction/magnetic-polaron in weak/strong electron-Mn coupling at low/high magnetic fields.