Localization and delocalization of fermions in a background of correlated spins

Abstract

We study the (de)localization phenomena of one-component lattice fermions in spin backgrounds. The O(3) classical spin variables on sites fluctuate thermally through the ordinary nearest-neighbor coupling. Their complex two-component (CP${}^1$-Schwinger boson) representation forms a composite U(1) gauge field on bond, which acts on fermions as a fluctuating hopping amplitude in a gauge invariant manner. For the case of antiferromagnetic (AF) spin coupling, the model has close relationship with the $t$-$J$ model of strongly-correlated electron systems. We measure the unfolded level spacing distribution of fermion energy eigenvalues and the participation ratio of energy eigenstates. The results for AF spin couplings suggest a possibility that, in two dimensions, all the energy eigenstates are localized. In three dimensions, we find that there exists a mobility edge, and estimate the critical temperature $T_{ßLD}(\delta )$ of the localization-delocalization transition at the fermion concentration $\delta$.

Version to appear in Phys. Rev. B

References in corpus (3)

• Critical parameters from generalised multifractal analysis at the Anderson transition
• Dynamical Localization in ${\mathbb{Z}}_2$ Lattice Gauge Theories
• Anderson Localization in Quark-Gluon Plasma

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• Magnetic-field-induced Anderson localization in orbital selective antiferromagnet BaMn${}_2$Bi${}_2$