Field-induced ferromagnetic phase transition in 2D Fermi systems with magnetic dipole-dipole interaction

TL;DR

This study investigates how external magnetic fields induce ferromagnetic phase transitions in a 2D Fermi gas with dipole-dipole interactions, highlighting controllable factors affecting spin polarization.

Contribution

It provides an explicit energy expression considering magnetic and dipolar interactions, revealing conditions for ferromagnetic phase transition in 2D Fermi systems.

Findings

Ferromagnetic transition occurs at sufficiently strong magnetic fields.

External magnetic field and dipolar interactions control spin polarization.

Explicit energy dependence on polarization, dipolar, and Zeeman parameters.

Abstract

Magnetic properties of the two-dimensional spin-polarized Fermi gas with dipole-dipole interaction are studied in the presence of external magnetic field at zero temperature. Within perturbation theory and the second quantization formalism, the total energy is explicitly obtained as a function of three dimensionless parameters, the spin polarization, dipolar coupling and Zeeman parameters. We examine the effects of these agents on the magnetic properties of 2D Fermi gas. The results show that an induced ferromagnetic phase transition is observed only for adequately large values of magnetic field. This paper offers two controllable factors to change the spin polarization of the system.