Indian J. Phys. 84 (6), 675-679 (2010) © 2010 IACS Lattice thermal conductivity of skutterudite compounds Banashree Saikia* and Priyanshu R Borthakur Department of Science and Technology University, Institute of Chartered Financial Analysts of India, Tripura-799 210, India E-mail : banashreemoni@rediffmail Abstract : A generalized expression is used on the basis of relaxation time approximation to facilitate calculation of lattice thermal conductivity of dielectric materials as well as skutterudite family consists of compounds of the form AB 3 . It is assumed that phonon scattering processes are independent and is represented by frequency dependent relaxation times. The contributions of normal three phonon scattering processes are included explicitly as redistribution of phonon momentum between two oscillation branches is considered. Magnitudes of relaxation times are estimated from the experimental data. The result for CoSb 3 is in reasonably good agreement with the experimental result in the temperature range 1-1000 0 K. It is observed that redistribution of phonon momentum between two oscillation branches leads to a significant suppression of thermal conductivity maximum and it is observed that for unfilled skutterudite the main dominant mechanism at the thermal conductivity maximum is three phonon normal scattering process. Keywords: Lattice thermal conductivity, normal process, relaxation time, dispersion curve, phonon Boltzmann equation. PACS Nos. : 63.20.Dj, 66.70.+f,63.20Kr 1. Introduction Recently skutterudite compounds are identified as a strong candidate for thermoelectric materials which is of the form AB 3 , where A is Co, Ir,or Rh and B is As, P or Sb. In the literature it is reported that the compound CoSb 3 behaves like semiconductor with a band gap of approximately 0.5eV and having large Seebeck coefficient [1]. For the use in the construction of efficient thermoelectric devices, a material should have higher electrical resistivity, low thermal conductivity and high Seebeck coefficient. So it is interested to study about thermal conductivity of CoSb 3 . Since the electronic contribution of thermal conductivity is very less (less than 10%), the main contribution of thermal conductivity is phonon contribution. *Corresponding Author