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Phys. Rev. Lett. 101, 037201 (2008) [4 pages]

Stable Mean-Field Solution of a Short-Range Interacting SO(3) Quantum Heisenberg Spin Glass

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C. M. S. da Conceição1 and E. C. Marino1,2
1Departamento de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
2Department of Physics, Princeton University, Princeton, New Jersey 08544, USA

Received 3 February 2008; published 14 July 2008

We present a mean-field solution for a quantum, short-range interacting, disordered, SO(3) Heisenberg spin model, in which the Gaussian distribution of couplings is centered in an antiferromagnetic (AF) coupling J̅ >0, and which, for weak disorder, can be treated as a perturbation of the pure AF Heisenberg system. The phase diagram contains, apart from a Néel phase at T=0, spin-glass and paramagnetic phases whose thermodynamic stability is demonstrated by an analysis of the Hessian matrix of the free-energy. The magnetic susceptibilities exhibit the typical cusp of a spin-glass transition.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.101.037201
DOI:
10.1103/PhysRevLett.101.037201
PACS:
75.10.Nr, 75.50.Lk