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 -