Volovik Effects in Fe-based Superconductors

Yunkyu Bang, Chonnam National University

In this talk, I will discuss specific heat and thermal conductivity in mixed state of Fe pnictide superconductors. Assuming the sign-changing s-wave gap (+/-s-wave gap) in the two band model, I show how Volovik effect occurs with an isotropic s-wave gaps in comparison to the well-known case of d-wave gap state. Including impurity scatterings, the field dependences of specific heat and thermal conductivity are, in general, in between H¹ and H^1/2, in good agreement with experiments of Co-doped Ba-122 compound.