Pauli metallic ground state in Hubbard clusters with Rashba spin-orbit coupling

We study the "phase diagram" of a Hubbard plaquette with Rashba spin-orbit coupling. We show that the peculiar way in which Rashba coupling breaks the spin-rotational symmetry of the Hubbard model allows a mixing of singlet and triplet components in the ground state that slows down and changes the nature of the Mott transition and of the Mott insulating phases. © 2018 American Physical Society.