[15a-A35-1~10] 9.4 Thermoelectric conversion

[15a-A35-1] [Young Scientist Presentation Award Speech] Mechanism of Phonon Thermal Conduction in Layered Oxides by Perturbed Molecular Dynamics

〇Susumu Fujii¹, Masato Yoshiya^1,2 (1.Osaka Univ., 2.JFCC)

Keywords:layered oxides, thermal conduction, molecular dynamics

Aiming at revealing the atomistic mechanism of phonon thermal conduction in layered cobaltites, we have performed calculations of phonon thermal conductivity using molecular dynamics method for Na_xCoO₂, Ca₃Co₄O₉, and Bi₂Sr₂Co₂O₉. It is found that the common CoO₂ layers transport large amount of heat though the volume ratio is relatively low compared with the neighboring layers, because the local thermal conductivity of CoO₂ layers is high. In addition, the phonon thermal conductivity of CoO₂ layers can be significantly reduced through interactions between CoO₂ and the neighboring layers. The origin will be discussed in terms of phenomenological understandings from vibrational analyses and quantitative understandings from frequency analyses of phonon thermal conduction.