2009/09/30 by A. Andreanov, Alexei Andreanov, J. T. Chalker +4 · 1 citation
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Degenerate energy levels #Frustration #Heisenberg model #Mathematics #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Randomness #Renormalization group #Spin glass #Spins #Statistical physics #Theoretical and Computational Physics #cond-mat.dis-nn #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevb.81.014406
published as Phys. Rev. B 81, 014406 (2010) · 10 pages. Published version.
openalex publication_date 2010/01/07 · arxiv created 2010/05/04 · arxiv updated 2010/05/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the effect in geometrically frustrated antiferromagnets of weak, random variations in the strength of exchange interactions. Without disorder the simplest classical models for these systems have macroscopically degenerate ground states, and this degeneracy may prevent ordering at any temperature. Weak exchange randomness favors a small subset of these ground states and induces a spin-glass transition at an ordering temperature determined by the amplitude of modulations in interaction strength. We use the replica approach to formulate a theory for this transition, showing that it falls into the same universality class as conventional spin-glass transitions. In addition, we show that a model with a low concentration of defect bonds can be mapped onto a system of randomly located pseudospins that have dipolar effective interactions. We also present detailed results from Monte Carlo simulations of the classical Heisenberg antiferromagnet on the pyrochlore lattice with weak randomness in nearest-neighbor exchange.