Interplane resistivity of underdoped single crystals (BaK)FeAs,
arXiv:1404.3664 · doi:10.1103/PhysRevB.89.144514
Abstract
Temperature-dependent inter-plane resistivity, , was measured in hole-doped iron-arsenide superconductor (BaK)FeAs over a doping range from parent compound to optimal doping , . Measurements were undertaken on high-quality single crystals grown from FeAs flux. The coupled magnetic/structural transition at leads to clear accelerated decrease of on cooling in samples with 26~K (). This decrease in hole-doped material is in notable contrast to an increase in in the electron-doped Ba(FeCo)Fe As and iso-electron substituted BaFe(AsP). The decreases very sharply with doping, dropping from =71~K to zero on increase of from approximately 25 to 27~K. The becomes -linear close to optimal doping. The broad crossover maximum in , found in the parent BaFeAs at around 200~K, shifts to higher temperature 250~K with doping =0.34. The maximum shows clear correlation with the broad crossover feature found in the temperature-dependent in-plane resistivity . The doping evolution of in (BaK)FeAs is in notable contrast with both rapid suppression of found in Ba(Fe)As (=Co,Rh,Ni,Pd) and its rapid increase BaFe(AsP). This observation suggest that pseudogap features are much stronger in hole-doped than in electron-doped iron-based superconductors, revealing significant electron-hole doping asymmetry similar to the cuprates. This paper replaces: cond-mat:1106.0533.