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arXiv · 1806.01432

Pressure tuned superconductivity and normal state behavior in Ba(Fe$_{0.943}$Co$_{0.057}$)$_2$As$_2$ near the antiferromagnetic boundary

W. Liu·Y. F. Wu·X. J. Li·S. L. Bud'ko·P. C. Canfield·C. Panagopoulos·P. G. Li·G. Mu·T. Hu·C. C. Almasan·H. Xiao
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Abstract

Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe-sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in Ba(Fe$_{1-x}$Co$_{x}$)$_2$As$_2$ single crystals with $x=$ 0.057, which is near the antiferromagnetic instability. Resistivity $\rho=\rho_0+AT^{n}$ was studied under applied pressure up to 7.90 GPa. The parameter $n$ approaches a minimum value of $n\approx 1$ at a critical pressure $P_c =$ 3.65 GPa. Near $P_c$, the superconducting transition temperature $T_c$ reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. These results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum $T_c$.

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W. Liu, Y. F. Wu, X. J. Li, S. L. Bud'ko, P. C. Canfield, C. Panagopoulos, P. G. Li, G. Mu, T. Hu, C. C. Almasan, H. Xiao. 2018-06-04. Pressure tuned superconductivity and normal state behavior in Ba(Fe$_{0.943}$Co$_{0.057}$)$_2$As$_2$ near the antiferromagnetic boundary. https://doi.org/10.1103/physrevb.97.144515

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