Phonon scattering effects on thermal conductivity of MgB2

Abstract A theoretical model is developed to account the anomalies reported for the thermal conductivity ( κ ) of MgB 2 superconductor. The inelastic neutron scattering shows that phonons are important in test material, we begin with the lattice thermal conductivity by incorporating the scattering of phonons with defects, grain boundaries, electrons as charge carriers, and phonons in the model Hamiltonian. Lattice κ dominates below T c and is attributed to strong phonon-defects, and impurity scattering mechanism. Furthermore, κ reveals power dependence at low temperatures. On the other hand, the contribution of careers towards κ is substantial and is due to the fact that the carriers are condensed, do not carry entropy. We argue that the response of κ in MgB 2 is determined by competition among several scatterings for carriers and a balance between carrier and phonon contributions.