We present a systematic study of resistivity and thermoelectric power for iron pnictide systems [formula omitted] and [formula omitted] for [formula omitted]. Both systems show a similar phase diagram with an antiferromagnetic (AFM) phase on the low-doping side and a superconducting dome-shaped phase at higher doping. The AFM phase intersects the superconducting phase boundary. The extrapolation of the AFM phase boundary to zero temperature defines a critical doping of [formula omitted]. We show that the electrical and thermoelectric transport properties above the superconducting [formula omitted] obey a characteristic temperature scaling behavior at [formula omitted]. The crossover and scaling property indicates the existence of a (possibly hidden) magnetic quantum critical point in the phase diagram of the 122 iron pnictides. The results of this investigation prove the significance of magnetic fluctuations in iron pnictide superconductors.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)