# Formation of localized magnetic states in a large-spin Fermi system

## TL;DR

This paper extends the Anderson impurity model to large-spin Fermi systems, analyzing magnetic phase formation and transitions in spin-3/2 ultracold Fermi atoms, revealing multiple magnetic phases with degenerate ground states.

## Contribution

It introduces a large-spin Fermi system model with spin 3/2, exploring magnetic phase diagrams and phase transitions, which is novel compared to previous models with smaller spins.

## Key findings

- Identification of three magnetic phases with different particle/hole occupations
- All phases exhibit four-fold degenerate ground states
- Phase transitions between phases are of first-order

## Abstract

We extend the Anderson impurity model to a large-spin Fermi system with spin $f$=3/2, stimulated by the realization of large-spin ultracold Fermi atoms. The condition required for the spontaneous formation of local magnetic moments is examined and the ground state mean-field magnetic phase diagram is explored carefully. We find that the spin-3/2 Fermi system involves magnetic phase regions I, II, and III that correspond to one, two, and three particle/hole occupation, respectively. In addition, it is observed that all the three magnetic phases have four-fold degenerate ground states. Finally, the phase transition between the three phases seems to be of the first-order.