Thermoelectric transport properties of gapless pinned charge density waves

TL;DR

This paper explores how new hydrodynamic coefficients in the effective theory of pinned charge density waves influence thermoelectric transport in strongly correlated quantum systems, using holographic models to explain phenomena in high-temperature superconductors.

Contribution

It demonstrates the impact of recently reinstated hydrodynamic coefficients on thermoelectric transport in models of pinned charge density waves, expanding the theoretical framework beyond Fermi liquid assumptions.

Findings

Novel hydrodynamic coefficients affect thermoelectric properties.

Sign change of Seebeck coefficient explained without Fermi surface reconstruction.

Low resistivity in CDW phase modeled with new coefficients.

Abstract

Quantum strongly correlated matter exhibits properties which are not easily explainable in the conventional framework of Fermi liquids. Universal effective field theory tools are applicable in these cases regardless of the microscopic details of the quantum system, since they are based on symmetries. It is necessary, however, to construct these effective tools in full generality, avoiding restrictions coming from particular microscopic descriptions which may inadequately constrain the coefficients that enter in the effective theory. In this work we demonstrate on explicit examples how the novel hydrodynamic coefficients which have been recently reinstated in the effective theory of pinned charge density waves (CDW) can affect the phenomenology of the thermo-electric transport in strongly correlated quantum matter. Our examples, based on two classes of holographic models with pinned CDW, have microscopics which are conceptually different from Fermi liquids. Therefore, the above novel transport coefficients are nonzero, contrary to the conventional approach. We show how these coefficients allow to take into account the change of sign of the Seebeck coefficient and the low resistivity of the CDW phase of the cuprate high temperature superconductors, without referring to the effects of Fermi surface reconstruction.