Divergent Thermopower without a Quantum Phase Transition

Kridsanaphong Limtragool and Philip W. Phillips
Phys. Rev. Lett. 113, 086405 – Published 22 August 2014

Abstract

A general principle of modern statistical physics is that divergences of either thermodynamic or transport properties are only possible if the correlation length diverges. We show by explicit calculation that the thermopower in the quantum XY model d=1+1 and the Kitaev model in d=2+1 can (i) diverge even when the correlation length is finite and (ii) remain finite even when the correlation length diverges, thereby providing a counterexample to the standard paradigm. Two conditions are necessary: (i) the sign of the charge carriers and that of the group velocity must be uncorrelated and (ii) the current operator defined formally as the derivative of the Hamiltonian with respect to the gauge field does not describe a set of excitations that have a particle interpretation, as in strongly correlated electron matter. Recent experimental and theoretical findings on the divergent thermopower of a 2D electron gas are discussed in this context.

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  • Received 21 March 2014

DOI:https://doi.org/10.1103/PhysRevLett.113.086405

© 2014 American Physical Society

Authors & Affiliations

Kridsanaphong Limtragool and Philip W. Phillips

  • Department of Physics and Institute for Condensed Matter Theory, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA

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Issue

Vol. 113, Iss. 8 — 22 August 2014

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