Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides

F. Hardy; P. Burger; T. Wolf; R. A. Fisher; P. Schweiss; P. Adelmann; R. Heid; R. Fromknecht; R. Eder; D. Ernst; H. v. Loehneysen; C. Meingast

doi:10.1209/0295-5075/91/47008

arXiv · 1007.2218

Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides

F. Hardy·P. Burger·T. Wolf·R. A. Fisher·P. Schweiss·P. Adelmann·R. Heid·R. Fromknecht·R. Eder·D. Ernst·H. v. Loehneysen·C. Meingast

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Abstract

An extensive calorimetric study of the normal- and superconducting-state properties of Ba(Fe1-xCox)2As2 is presented for 0 < x < 0.2. The normal-state Sommerfeld coefficient increases (decreases) with Co doping for x < 0.06 (x > 0.06), which illustrates the strong competition between magnetism and superconductivity to monopolize the Fermi surface in the underdoped region and the filling of the hole bands for overdoped Ba(Fe1-xCox)2As2. All superconducting samples exhibit a residual electronic density of states of unknown origin in the zero-temperature limit, which is minimal at optimal doping but increases to the normal-state value in the strongly under- and over-doped regions. The remaining specific heat in the superconducting state is well described using a two-band model with isotropic s-wave superconducting gaps.

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F. Hardy, P. Burger, T. Wolf, R. A. Fisher, P. Schweiss, P. Adelmann, R. Heid, R. Fromknecht, R. Eder, D. Ernst, H. v. Loehneysen, C. Meingast. 2010-07-13. Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides. https://doi.org/10.1209/0295-5075%2F91%2F47008

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