Thermopower in Overdoped Region of Cuprates

TL;DR

This study investigates the thermoelectric power in overdoped cuprate superconductors, revealing deviations from Fermi liquid behavior likely due to a density of states singularity near the Fermi level, supported by experimental and theoretical analysis.

Contribution

It provides new insights into the non-metallic behavior of overdoped cuprates by linking thermopower deviations to a density of states singularity near the Fermi level.

Findings

Thermopower deviates from T-linear behavior in overdoped cuprates.

Susceptibility results support the non-metallic behavior.

Comparison with a tight-binding model suggests a density of states singularity.

Abstract

The thermoelectric power S(T) of single-layer Bi2Sr2CuO6+d is studied as a function of oxygen doping in the strongly overdoped region of the phase diagram (T, d). As other physical properties in this region, diffusion thermopower Sdiff(T) also shows an important deviation from conventional Fermi liquid behaviour. This departure from T-linear S(T) dependence together with the results of susceptibility on the same samples suggest that the origin of the observed non-metallic behaviour is the existence of a singularity in the density of states near the Fermi level. The doping and temperature dependence of themopower is compared with a tight-binding band model.