TY - JOUR

T1 - Divergent thermopower without a quantum phase transition

AU - Limtragool, Kridsanaphong

AU - Phillips, Philip W.

PY - 2014/8/22

Y1 - 2014/8/22

N2 - 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.

AB - 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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U2 - 10.1103/PhysRevLett.113.086405

DO - 10.1103/PhysRevLett.113.086405

M3 - Article

AN - SCOPUS:84907353254

SN - 0031-9007

VL - 113

JO - Physical review letters

JF - Physical review letters

IS - 8

M1 - 086405

ER -