Polaron-like conduction in iron pnictides of the Ln-1111 and Æ-122 families

Manuel Nunez-Regueiro (1)

1 NEEL - MagSup - Magnétisme et Supraconductivité

The examination of the electrical resistivities of iron pnictides shows that they follow a T exp(Ea/kBT) temperature dependence. The activation energies Ea show a linear behaviour with the critical temperatures of the spin density waves (SDW), T , as both vary with pressure. The slope matches the ratio SDW gap to T , while the intercept can be related to the transition temperature of the lattice distortion, T0. An adapted Landau free energy predicts the observed order of the transitions, according to which is higher, T or T0. We discuss our analysis within the framework of polarons.

Domaines: Supraconductivité [cond-mat.supr-con]

Manuel Nunez-Regueiro. Polaron-like conduction in iron pnictides of the Ln-1111 and Æ-122 families. EPL - Europhysics Letters, 2009, 88 (3), pp.37004. ⟨10.1209/0295-5075/88/37004⟩. ⟨hal-00977938⟩