Electronic Inhomogeneity and Breakdown of the Universal Thermal Conductivity of Cuprate Superconductors

Abstract

We report systematic, high-precision measurements of the low-T (down to 70 mK) thermal conductivity kappa of YBa2Cu3O(y), La(2-x)Sr(x)CuO4, and Bi2Sr2CaCu2O(8+delta). Careful examinations of the Zn- and hole-doping dependences of the residual thermal conductivity kappa0/T, as well as the in-plane anisotropy of kappa0/T in Bi2Sr2CaCu2O(8+delta), indicate a breakdown of the universal thermal conductivity, a notable theoretical prediction for d-wave superconductors. Our results point to an important role of electronic inhomogeneities, which are not considered in the standard perturbation theory for thermal conductivity, in the underdoped to optimally doped regime.

Thermal conductivity ofIPA-CuCl3: Evidence for ballistic magnon transport and the limited applicability of the Bose-Einstein condensation model

“…1,2 The well-known T 3 ballistic behavior of phonons, however, has been rarely observed in the transition-metal compounds, including the high-T c cuprates, the multiferroic manganites and the low-dimensional quantum magnets. 7,20,22,31,32,[34][35][36][37][38][39] In the boundary scattering limit, the phonon thermal conductivity of an isotropic system is given by…”

Possible Sign-Reversings-Wave Superconductivity in Co-Doped BaFe2As2Proved by Thermal Transport Measurements

“…17 In fact, the impurity concentration independent κ 0 /T has been observed in high-T c superconductors, 18 although its universality is still under debate. 19 Theoretically, the universal thermal conductivity κ 00 /T for the nodal superconductor is explicitly expressed as…”

Pomeranchuk instability in a non-Fermi liquid from holography

“…These studies show that in these cases there are symmetrical Fermi surfaces in the boundary theory whose underlying excitations can either be Fermi or non-Fermi liquid-like. On the other hand, when ϕ xx develops a normalizable 3 There is also a coupling of the form λ 5 √ −g ϕµνψ Γ 5 Γ µ D ν ψ that breaks parity in the boundary theory when the operator dual to ϕµν condenses. We will not consider such a coupling in this paper.…”

“…As such, systems undergoing a Pomeranchuk instability exhibit manifestly distinct transport properties along the different crystal axes. Experimentally several instances of anisotropic transport in strongly correlated electronic systems have been reported [2][3][4][5] and occupy much of the current focus in correlated electron matter. Although it is unclear at present whether the Pomeranchuk mechanism is the only root cause 2 , it nevertheless offers a framework where such anisotropies can be characterized in detail.…”

“…For reviews on the applications of holography for condensed matter physics, see [11][12][13][14][15][16][17]. We take the system to be d = 2 + 1 dimensional, as this is the most interesting case experimentally [2][3][4][5]. Also, we consider the case where the broken phase is a nematic (non-)Fermi liquid with the symmetry of a quadrupole.…”