Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe

An extensive calorimetric study of the normal- and superconducting-state properties of Ba(Fe1−xCox)2As2 is presented for 00.06), 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