Investigations of collective phonon behaviours in lattice thermal conductivity

2015 Fiscal Year Final Research Report

• Project/Area Number: 26820284
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Kyoto University
• Principal Investigator: Atsushi Togo 京都大学, 構造材料元素戦略研究拠点ユニット, 准教授 (10610529)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: フォノン / フォノン間相互作用 / 格子熱伝導 / 第一原理計算

Outline of Final Research Achievements

Phonon-phonon interactions, phonon lifetimes, and lattice thermal conductivities of a variety of crystals were investigated using first-principles anharmonic lattice dynamics calculations. The lattice thermal conductivities of 101 different crystals of zincblende-, wurtzite-, and rocksalt-types were systematically calculated. It was found that scatterings among phonons are governed by the detailed combinations of phonon energies, momentums, and phonon-phonon interaction strengths. This showed difficulty of prediction of lattice thermal conductivity by simple phonon models. We made an investigation of prediction of lattice thermal conductivities using a machine learning approach and this successfully predicted unknown low lattice thermal conductivity materials, which indicates further studies are necessary to understand lattice thermal conductivity mechanism from the viewpoint of chemical bondings.

Free Research Field

第一原理格子動力学計算