Abstract
We study the effect of hole doping and chemical pressure (isovalent doping) in single crystals of KEuFeAs and EuFe(AsP), respectively, by measuring the thermopower, , and electrical resistivity, . The evolution of upon doping indicates drastic changes in the electronic configuration at critical values and , respectively, as the spin-density-wave transition is completely suppressed and superconductivity (SC) emerges. For the case of chemical pressure, a comparison with published ARPES measurements indicates a Lifshitz transition at . The temperature dependences and observed in the normal state above the SC transition suggest quantum criticality in both systems.
3 More- Received 1 November 2011
DOI:https://doi.org/10.1103/PhysRevB.85.024511
©2012 American Physical Society