First- and second-order metal-insulator phase transitions and topological aspects of a Hubbard-Rashba system

Abstract

This paper considers a model consisting of a kinetic term, Rashba spin-orbit coupling and short-range Coulomb interaction at zero-temperature. The Coulomb interaction is decoupled by a mean-field approximation in the spin channel using field theory methods. The results feature a first-order phase transition for any finite value of the chemical potential and quantum criticality for vanishing chemical potential. The Hall conductivity is also computed using Kubo formula in a mean-field effective Hamiltonian. In the limit of infinite mass the kinetic term vanishes and all the phase transitions are of second order, in this case spontaneous symmetry breaking mechanism adds a ferromagnetic metallic phase to the system and features a zero-temperature quantization of the Hall conductivity in the insulating one.

Spin texture in a bilayer high-temperature cuprate superconductor

“…The interplay or competition between SOC and electron correlations is relevant in systems like the heavy fermion superlattices [4], iridium oxides [5], and optical lattices [6], in which exotic phases are expected. Within the Rashba-Hubbard model, a mixed singlet-triplet superconducting state [7][8][9][10][11][12][13][14][15], novel magnetism [16,17], and nontrivial topological properties [12,[18][19][20] are theoretically predicted.…”