New Journal of Physics (Jan 2013)

A crossover in the phase diagram of NaFe1−xCoxAs determined by electronic transport measurements

  • A F Wang,
  • J J Ying,
  • X G Luo,
  • Y J Yan,
  • D Y Liu,
  • Z J Xiang,
  • P Cheng,
  • G J Ye,
  • L J Zou,
  • Z Sun,
  • X H Chen

DOI
https://doi.org/10.1088/1367-2630/15/4/043048
Journal volume & issue
Vol. 15, no. 4
p. 043048

Abstract

Read online

We report electronic transport measurements on single crystals of the NaFe _1− _x Co _x As system. We found that the cotangent of the Hall angle, cot θ _H , follows T ^4 for the parent compound with filamentary superconductivity and T ^2 for the heavily overdoped non-superconducting sample. However, it exhibits approximately T ^3 -dependence in all the samples with bulk superconductivity, suggesting that this behavior is associated with bulk superconductivity in ferropnictides. A deviation develops below a characteristic temperature T * well above the structural and superconducting transitions, accompanied by a departure from power-law temperature dependence in resistivity. The doping dependence of T * resembles the crossover line of the pseudogap phase in cuprates.