Fermionic van Hemmen spin glass model with a transverse field |
| |
Authors: | SG Magalhaes FM Zimmer |
| |
Institution: | a Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil b Instituto de Fisica, Universidade Federal Fluminense, 24210-346 Niterói, RJ, Brazil |
| |
Abstract: | In the present work it is studied the fermionic van Hemmen model for the spin glass (SG) with a transverse magnetic field Γ. 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 Γ. 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 μ and Γ. The Γ field suppresses the magnetic orders. The increase of μ 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 μ. In addition, μ can change the nature of the phase boundaries introducing a first order transition. |
| |
Keywords: | Quantum spin glass Fermionic model Charge fluctuation |
本文献已被 ScienceDirect 等数据库收录! |
|