Magnetic and quadrupolar order in a one-dimensional ferromagnet with cubic crystal-field anisotropy

TL;DR

This study investigates a one-dimensional S=2 ferromagnetic chain with cubic anisotropy, revealing a transition from magnetic to quadrupolar order at zero temperature, characterized by continuous Ising-like critical behavior.

Contribution

It provides the first numerical evidence of a purely quadrupolar phase in a simple ferromagnetic model without explicit quadrupolar interactions.

Findings

Existence of a quadrupolar phase at large anisotropy

Continuous phase transition with Ising critical exponents

Phase diagram mapped using DMRG methods

Abstract

The zero temperature phase diagram of a one-dimensional S=2 Heisenberg ferromagnet with single-ion cubic anisotropy is studied numerically using the density-matrix renormalization group method. Evidence is found that although the model does not involve quadrupolar couplings, there is a purely quadrupolar phase for large values of the anisotropy. The phase transition between the magnetic and quadrupolar phases is continuous and it seems to be characterized by Ising critical exponents.