Thermoelectric properties of electron- and hole-dopedBaFe2As2

Abstract

We investigate the resistivity and thermoelectric power properties for Co- or K-doped ${\text{BaFe}}_{2}{\text{As}}_{2}$ systems. ${T}_{c}$ as a function of Co- or K-doping level exhibits a domelike behavior in both of the systems. The thermoelectric power $(S)$ at room temperature as a function of doping level $(x)$ shows a domelike behavior in ${\text{Ba}}_{1\ensuremath{-}x}{\text{K}}_{x}{\text{Fe}}_{2}{\text{As}}_{2}$ system while monotonously decreases in ${\text{BaFe}}_{2\ensuremath{-}x}{\text{Co}}_{x}{\text{As}}_{2}$ system. It is intriguing that the superconducting samples simultaneously show large absolute values of thermoelectric power and good conductivity. The power factor shows a peak at low temperature, suggesting possible applications in thermoelectric cooling modules around the liquid-nitrogen temperature range.