Autori: C R Rotundu, B Freelon, S D Wilson, G Pinuellas, A Kim, E. Bourret-Courchesne, N E Phillips, and R J Birgeneau

Editorial: IOP Publishing, Journal of Physics: Conference Series , 273, p.012103, 2011.

Rezumat:

Heat-capacity measurements on exceptionally high-quality samples of Ba1−xKxFe2As2 give the values of a number of parameters relevant to the electronic structure, the structural/magnetic transition in the undoped parent compound, and the superconducting transition in the near optimally doped, x = 0.41 sample. In BaFe2As2 the changes in the lattice
and magnetic structure appear as a single, sharp first-order transition at 140 K; the Sommerfeld coefficient is gamma = 5.1 mJ K-2 mol-1. For the superconducting, x = 0.41, sample, the residual density of electron states in the superconducting states is essentially zero. The specific-heat
anomaly at Tc suggests extreme strong coupling, with Delta(0)/k_BTc = 2.6, and a normal-state Sommerfeld coefficient gamma_n = 45 mJ K-2 mol-1.

Cuvinte cheie: 1111, 122 pnictide

URL: http://people.lbl.gov/~rotundu/pdfs/SCES2010_273_012103.pdf