Lorenz Number in High Tc Superconductors: Evidence for Bipolarons

K. K. Lee; A. S. Alexandrov; W. Y. Liang

doi:10.1103/PhysRevLett.90.217001

← Back to search

Lorenz Number in High Tc Superconductors: Evidence for Bipolarons

K. K. Lee, A. S. Alexandrov, W. Y. Liang

DOI 10.1103/PhysRevLett.90.217001 · Physical Review Letters

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

The strong electron-phonon interaction in cuprates has gathered support over the last decade in a number of experiments. While phonons remain almost unrenormalized, electrons are transformed into itinerant bipolarons and thermally excited polarons when the electron-phonon interaction is strong. We calculate the Lorenz number of the system to show that the Wiedemann-Franz law breaks down because of the interference of polaron and bipolaron contributions in the heat flow. The model fits numerically the experimental Hall Lorenz number, which provides direct evidence for bipolarons in the cuprates.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O6+x Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
YBa2Cu3O6.95 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Tl2Ba2CuO6+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown