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arXiv · 0912.5244

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

Priyanka Mohan·Rajesh Narayanan·Thomas Vojta
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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.

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Priyanka Mohan, Rajesh Narayanan, Thomas Vojta. 2010-04-07. Infinite randomness and quantum Griffiths effects in a classical system: the randomly layered Heisenberg magnet. https://doi.org/10.1103/physrevb.81.144407

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