A mean-field theory for strongly disordered non-frustrated antiferromagnets

Abstract

Motivated by impurity-induced magnetic ordering phenomena in spin-gap materials like TlCuCl3, we develop a mean-field theory for strongly disordered antiferromagnets, designed to capture the broad distribution of coupling constants in the effective model for the impurity degrees of freedom. Based on our results, we argue that in the presence of random magnetic couplings the conventional first-order spin-flop transition of an anisotropic antiferromagnet is split into two transitions at low temperatures, associated with separate order parameters along and perpendicular to the field axis. We demonstrate the existence of either a bicritcal point or a critical endpoint in the temperature-field phase diagram, with the consequence that signatures of the spin flop are more pronounced at elevated temperature.

arXiv comment8 pages, 8 figs; (v2) final version as published

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Cited by in corpus (7)

• Supplementary material for "Impurity-induced magnetic order in low dimensional spin gapped materials"
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• Stochastic Mean-Field Theory for the Disordered Bose-Hubbard Model
• Disordered driven coupled cavity arrays: Non-equilibrium stochastic mean-field theory
• Correlations in Quantum Spin Ladders with Site and Bond Dilution
• Disorder effects in the quantum Heisenberg model: An Extended Dynamical mean-field theory analysis
• Ground state properties of the disordered spin-one Bose-Hubbard model: a stochastic mean-field theory study