Quantum critical scaling behavior of deconfined spinons

Nogueira, Flavio S.; Kragset, Steinar; Sudbo, Asle

Quantum critical scaling behavior of deconfined spinons

Authors

Nogueira, Flavio S.

Kragset, Steinar

Sudbo, Asle

Description

We perform a renormalization group analysis of some important effective field theoretic models for deconfined spinons. We show that deconfined spinons are critical for an isotropic SU(N) Heisenberg antiferromagnet, if $N$ is large enough. We argue that nonperturbatively this result should persist down to N=2 and provide further evidence for the so called deconfined quantum criticality scenario. Deconfined spinons are also shown to be critical for the case describing a transition between quantum spin nematic and dimerized phases. On the other hand, the deconfined quantum criticality scenario is shown to fail for a class of easy-plane models. For the cases where deconfined quantum criticality occurs, we calculate the critical exponent $η$ for the decay of the two-spin correlation function to first-order in $ε=4-d$. We also note the scaling relation $η=d+2(1-ϕ/ν)$ connecting the exponent $η$ for the decay to the correlation length exponent $ν$ and the crossover exponent $ϕ$.
4.1 pages, no figures, references added; Version accepted for publication in PRB (RC)