Thermopower in the strongly overdoped region of single-layer Bi 2 Sr 2 CuO 6 + δ superconductor

The evolution of the thermoelectric power $S(T)$ with doping p of single-layer ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CuO}}_{6+\ensuremath{\delta}}$ ceramics in the strongly overdoped region is studied in detail. Analysis in terms of drag and diffusion contributions indicates a departure of the diffusion from the T-linear metallic behavior. This effect is increased in the strongly overdoped range $(p\ensuremath{\sim}0.2\char21{}0.28)$ and should reflect the proximity of some topological change.