Rationalizing phonon dispersion for lattice thermal conductivity of solids

• 来源期刊: 国家科学评论（英文版）
• 关键词: thermoelectric thermal conductivity minimal thermal conductivity phonon dispersion
• 年，卷（期）: 2018,（6）
• 页码范围: 888-894
• 页数: 7页
• 语种: 英文
• DOI: 10.1093/nsr/nwy097

摘要

Lattice thermal conductivity (κL) is one of the most fundamental properties of solids.The acoustic-elastic-wave assumption,proposed by Debye (Debye P.Ann Phys 1912;344:789-839),has led to linear phonon dispersion being the most common approximation for understanding phonon transport over the past century.Such an assumption does not take into account the effect of a periodic boundary condition on the phonon dispersion,originating from the nature of periodicity on atomic arrangements.Driven by modem demands on the thermal functionality of materials,with κL ranging from ultra-low to ultra-high,any deviation from the Debye approximation in real materials becomes more and more significant.This work takes into account the periodic boundary condition,and therefore rationalizes the phonon dispersion to be more realistic.This significantly improves the precision for quickly predicting κL without any fitting parameters,as demonstrated in hundreds of materials,and offers a theoretical basis rationalizing κL to be lower than the minimum currently accepted based on the Debye dispersion.This work paves the way for designing solids with expected κ L and particularly inspires the advancement oflow-κ L materials for thermal energy applications.