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

TL;DR

This paper investigates magnetic phase transitions in 1D quantum dot arrays coupled with leads using various theoretical methods, revealing conditions for different magnetic states and dynamic transitions.

Contribution

It combines multiple advanced methods to analyze magnetic phase transitions in quantum dot arrays, providing new insights into their static and dynamic behaviors.

Findings

Anti-ferromagnetic states occur in odd-numbered or staggered-hopping arrays at weak coupling.

Increasing coupling or bias induces magnetism-to-non-magnetism phase transitions.

Dynamic phase transition processes are characterized using the HEOM method.

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.