Fermionic van Hemmen Spin Glass Model with a Transverse Field

TL;DR

This paper investigates the fermionic van Hemmen spin glass model with a transverse field, analyzing how quantum fluctuations and chemical potential influence magnetic phases and phase transitions.

Contribution

It introduces a fermionic formulation of the van Hemmen spin glass model with a transverse field and explores the effects of charge fluctuations on magnetic phase diagrams.

Findings

Transverse field suppresses magnetic order.

Chemical potential alters occupation and phase boundaries.

Phase transitions can change from second to first order.

Abstract

In the present work it is studied the fermionic van Hemmen model for the spin glass (SG) with a transverse magnetic field $\Gamma$. In this model, the spin operators are written as a bilinear combination of fermionic operators, which allows the analysis of the interplay between charge and spin fluctuations in the presence of a quantum spin flipping mechanism given by $\Gamma$. The problem is expressed in the fermionic path integral formalism. As results, magnetic phase diagrams of temperature versus the ferromagnetic interaction are obtained for several values of chemical potential $\mu$ and $\Gamma$. The $\Gamma$ field suppresses the magnetic orders. The increase of $\mu$ alters the average occupation per site that affects the magnetic phases. For instance, the SG and the mixed SG+ferromagnetic phases are also suppressed by $\mu$. In addition, $\mu$ can change the nature of the phase boundaries introducing a first order transition.