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

TL;DR

This paper investigates how Rashba spin-orbit coupling influences the ground state and phase transitions in small Hubbard clusters, revealing a mixing of spin states and altered Mott transition characteristics.

Contribution

It demonstrates that Rashba coupling modifies the ground state by mixing singlet and triplet components, affecting the Mott transition in Hubbard clusters.

Findings

Rashba coupling breaks spin-rotational symmetry in Hubbard clusters.

Mixing of singlet and triplet components occurs in the ground state.

The nature of the Mott transition is significantly altered.

Abstract

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 it changes the nature of the Mott transition and of the Mott insulating phases.