Infinite randomness and quantum Griffiths effects in a classical system: the randomly layered Heisenberg magnet

Abstract

We investigate the phase transition in a three-dimensional classical Heisenberg magnet with planar defects, i.e., disorder perfectly correlated in two dimensions. By applying a strong-disorder renormalization group, we show that the critical point has exotic infinite-randomness character. It is accompanied by strong power-law Griffiths singularities. We compute various thermodynamic observables paying particular attention to finite-size effects relevant for an experimental verification of our theory. We also study the critical dynamics within a Langevin equation approach and find it extremely slow. At the critical point, the autocorrelation function decays only logarithmically with time while it follows a nonuniversal power-law in the Griffiths phase.

10 pages, 2 eps figures included, final version as published.

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Cited by in corpus (11)

• Disorder in quantum many-body systems
• Strong Disorder RG approach - a short review of recent developments
• An Anomalously Elastic, Intermediate Phase in Randomly Layered Superfluids, Superconductors, and Planar Magnets
• Influence of superohmic dissipation on a disordered quantum critical point
• Breakdown of self-averaging in the Bose glass
• Sliding phase in randomly stacked 2D superfluids/superconductors
• Highly-symmetric random one-dimensional spin models
• Infinite-randomness criticality in a randomly layered Heisenberg magnet
• Anomalous elasticity in a disordered layered XY model
• Monte Carlo simulations of a disordered superconductor-metal quantum phase transition
• Evidence for power-law Griffiths singularities in a layered Heisenberg magnet