Dr. Jiawang Hong [Beijing Institute of Technology, China]

Title: Anharmonic lattice dynamics and elasticity of energy materials under high pressure from first-principles calculations and inelastic x-ray/neutron scattering measurements

Time: 10:00 - 11:00 AM, Tuesday, July 19, 2016

Place: Auditorium Room 410, HPSTAR (Shanghai)

Abstract:

Harmonic and quasi-harmonic models of lattice dynamics are widely successful in explaining thermodynamic properties of materials. However, in some cases, strong anharmonicity can critically affect physical properties, and a (quasi) harmonic model is not sufficient to capture these important features. In this talk, I will show that the strong anharmonicity play a critical role in two important systems: promising thermoelectric material SnSe [1,2] and metal-insulator transition material VO2 [3]. By combining inelastic x-ray/neutron scattering measurements and first-principles calculations, we have investigated the lattice dynamics, and their important role in the ultralow thermal conductivity in thermoelectric SnSe and the thermodynamics of metal-insulator phase transition in VO2. The anharmonicity and elasticity under high pressure will also be discussed.

1. C.W. Li*,JW Hong*, A.F. May, D. Bansal, S. Chi, T. Hong, G. Ehlers, and O. Delaire, Nature Physics, 11, 1063 (2015)

2. JW Hong and O. Delaire,  arXiv:1604.07077

3. J Budai*, JW Hong*, M Manley, E Specht, CW Li, JZ Tischler, DL Abernathy, AH Said, BM Leu, LA Boatner, RJ McQueeney and O Delaire, Nature, 515, 535 (2014).

Biography of the Speaker:

洪家旺，北京理工大学教授，博士生导师。2004年本科毕业于湖南大学，2010年在清华大学获得博士学位，期间2007-2008年在英国剑桥大学进行交流访问。2010至2016年分别在美国Rutgers大学和橡树岭国家实验室从事博士后研究工作。他的主要研究方向为结合第一性原理计算和非弹性中子/同步辐射散射测量，研究功能材料和能源材料的晶格动力学性能以及力、电、磁和热的耦合效应。