Heat conduction analysis on nanostructured bulk thermoelectric materials from first principles

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K17982
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Thermal engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Shiga Takuma 東京大学, 大学院工学系研究科(工学部), 助教 (10730088)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: フォノン / 界面熱輸送 / フォノンコヒーレンス / 熱電変換 / 分子動力学法 / 格子動力学法 / グリーン関数 / 第一原理計算

Outline of Final Research Achievements

In order to realize high-performance thermoelectric materials, we have developed the method calculating phonon transport spectra inside a material and at an interface, and obtained a guidance of structuring for effectively reducing phonon transports contributing to overall heat conduction. As for the manipulation of heat conduction utilizing wave nature of phonons, we have evaluated impacts of interference and resonance by nanostructured interface on the reduction of thermal conductivity by means of phonon-wave packet and atomistic Green's function methods. Besides this, we performed molecular dynamics simulations to estimate phonon coherence length, which is important length scale in structural control utilizing wave nature of phonons. As results, we identified that, similar with phonon mean free path, coherence length is strongly dependent on frequency and widely distributed from 1 to 100 nm.

Free Research Field

熱工学