We present Monte Carlo simulations of a two-dimensional bilayer quantum Heisenberg antiferromagnet with random dimer dilution. In contrast with exotic scaling scenarios found in other random quantum systems, the quantum phase transition in this system is characterized by a finite-disorder fixed point with power-law scaling. After accounting for corrections to scaling, with a leading irrelevant exponent of ω≈0.48, we find universal critical exponents z=1.310(6) and ν=1.16(3). We discuss the consequences of these findings and suggest new experiments.
R. Sknepnek et al., "Exotic vs. Conventional Scaling and Universality in a Disordered Bilayer Quantum Heisenberg Antiferromagnet," Physical Review Letters, American Physical Society (APS), Jan 2004.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevLett.93.097201
DFG Center for Functional Nanostructures Karlsruhe
National Science Foundation (U.S.)
University of Missouri Research Board
Keywords and Phrases
Monte Carlo Methods; Antiferromagnetic Materials; Hamiltonians; Phase Transitions; Random Processes; Computer simulation; Dimers; Fermions; Mathematical models; Parameter estimation
Article - Journal
© 2004 American Physical Society (APS), All rights reserved.