Degeneracy and Strong Fluctuation-Induced First-Order Phase Transition in the Dipolar Pyrochlore Antiferromagnet

TL;DR

This paper investigates how degeneracy of soft modes influences the first-order phase transition in dipolar pyrochlore antiferromagnets, supported by simulations and theoretical analysis, explaining experimental observations in Gd(2)Sn(2)O(7).

Contribution

It demonstrates that degeneracy of critical modes enhances the first-order transition in dipolar pyrochlore antiferromagnets, combining Monte-Carlo simulations and renormalization group analysis.

Findings

Degeneracy of soft modes amplifies the first-order transition.

Monte-Carlo simulations support the degeneracy effect.

Theoretical analysis explains experimental results in Gd(2)Sn(2)O(7).

Abstract

We show that a continuous set of degenerate critical soft modes strongly enhances the first-order character of a fluctuation-induced first-order transition in the pyrochlore dipolar Heisenberg antiferromagnet. Such a degeneracy seems essential to explain the strong first-order transition recently observed in Gd(2)Sn(2)O(7). We present some evidence from Monte-Carlo simulations and a perturbative renormalization group expansion.