Magnetization processes and existence of reentrant phase transitions in coupled spin-electron model on doubly decorated planar lattices

TL;DR

This paper introduces a coupled spin-electron model on doubly decorated lattices, analyzing its phase diagrams and magnetization behavior, revealing rich ground states, tunable magnetization plateaus, and reentrant phase transitions driven by temperature and magnetic field.

Contribution

The study presents a new coupled spin-electron model analyzed with advanced methods, uncovering complex phase diagrams and reentrant transitions not previously characterized.

Findings

Rich ground-state phase diagrams depending on electron hopping and magnetic field

Tunable intermediate magnetization plateaus via electron density

Existence of reentrant phase transitions driven by temperature or magnetic field

Abstract

An alternative model for a description of magnetization processes in coupled 2D spin-electron systems has been introduced and rigorously examined using the generalized decoration-iteration transformation and the corner transfer matrix renormalization group method. The model consists of localized Ising spins placed on nodal lattice sites and mobile electrons delocalized over the pairs of decorating sites. It takes into account a hopping term for mobile electrons, the Ising coupling between mobile electrons and localized spins as well as the Zeeman term acting on both types of particles. The ground-state and finite-temperature phase diagrams were established and comprehensively analyzed. It was found that the ground-state phase diagrams are very rich depending on the electron hopping and applied magnetic field. The diversity of magnetization curves can be related to intermediate magnetization plateaus, which may be continuously tuned through the density of mobile electrons. In addition, the existence of several types of reentrant phase transitions driven either by temperature or magnetic field was proven.