6533b829fe1ef96bd128a476
RESEARCH PRODUCT
Low-energy fixed points of random Heisenberg models
Heiko RiegerYu-cheng LinFerenc IglóiRégis Mélinsubject
PhysicsStatistical Mechanics (cond-mat.stat-mech)Condensed matter physicsInfrared fixed pointFOS: Physical sciencesDisordered Systems and Neural Networks (cond-mat.dis-nn)Type (model theory)Fixed pointRenormalization groupCondensed Matter - Disordered Systems and Neural NetworksOmegaExponentCondensed Matter::Strongly Correlated ElectronsRandomnessCondensed Matter - Statistical MechanicsSpin-½Mathematical physicsdescription
The effect of quenched disorder on the low-energy and low-temperature properties of various two- and three-dimensional Heisenberg models is studied by a numerical strong disorder renormalization group method. For strong enough disorder we have identified two relevant fixed points, in which the gap exponent, omega, describing the low-energy tail of the gap distribution, P(Delta) ~ Delta^omega is independent of disorder, the strength of couplings and the value of the spin. The dynamical behavior of non-frustrated random antiferromagnetic models is controlled by a singlet-like fixed point, whereas for frustrated models the fixed point corresponds to a large spin formation and the gap exponent is given by omega ~ 0. Another type of universality classes is observed at quantum critical points and in dimerized phases but no infinite randomness behavior is found, in contrast to one-dimensional models.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2002-11-19 |