Randomly diluted S=1/2 Heisenberg antiferromagnet on the bilayer square lattice
Abstract
It has recently been shown that the dilution induced order-disorder transition in the 2D Heisenberg antiferromagnet occurs exactly at the percolation point [K. Kato et al., Phys. Rev. Lett. 84, 4204 (2000)] and that this is a purely classical percolation transition [A. W. Sandvik, Phys. Rev. Lett. 86, 3209 (2001) and cond-mat/0110510]. In a bilayer geometry, the Heisenberg model undergoes an order-disorder transition at a critical value of the inter-layer coupling. If this system is diluted by randomly removing dimers, the transition point moves towards weaker inter-layer couplings. At the percolation point the critical coupling remains non-zero, as expected in view of the behavior of the single-layer system. At this special point the percolating cluster is quantum critical. I will discuss the critical properties of this point, as obtained using large-scale quantum Monte Carlo simulations, as well as the relevance of disorder away from this point [A. W. Sandvik and O. Sushkov, preprint].
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2002
- Bibcode:
- 2002APS..MAR.U2003S