Steady and dynamic magnetic phase transitions in interacting quantum dots arrays coupled with leads

Abstract

We apply the Hubbard model, non-equilibrium Green's function (NEGF) theory, exact diagonalization (ED) and the hierarchical equations of motion (HEOM) method to investigate abundant magnetic phase transitions in the 1D interacting quantum dots arrays (QDA) sandwiched by non-interaction leads. The spin polarization phase transitions are firstly studied with a mean-field approximation. The many-body calculation of the ED method is then used to verify such transitions. We find with the weak device-leading couplings, the anti-ferromagnetic (AF) state only exists in the uniform odd-numbered QDA or the staggered-hopping QDA systems. With increasing the coupling strength or the bias potentials, there exists the magnetism-to non-magnetism phase transition. With the spin-resolved HEOM method we also investigate the detailed dynamic phase transition process of these lead-QDA-lead systems.Comment: 17 pages, 6 figure