Canted phase in double quantum dots

We perform a Hartree-Fock calculation in order to describe the ground state of a vertical double quantum dot in the absence of magnetic fields parallel to the growth direction. Intradot and interdot exchange interactions determine the singlet or triplet character of the system as the tunneling is tuned. At finite Zeeman splittings due to in-plane magnetic fields, we observe a quantum phase transition from a ferromagnetic to a symmetric phase through a canted antiferromagnetic state. The latter is obtained even at zero Zeeman energy for an odd number of electrons.