Can Nano-Particle Melt below the Melting Temperature of Its Free Surface Partner?

作     者：眭晓红 王宗国 康凯 覃绍京 王垂林 

作者机构：State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Computer Network Information Center Chinese Academy of Sciences Science and Technology on Surface Physics and Chemistry Laboratory China Center of Advanced Science and Technology 

出 版 物：《Communications in Theoretical Physics》 (理论物理通讯（英文版）)

年 卷 期：2015年第63卷第2期

页      面：249-254页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Supported by National Natural Science Foundation of China under Grant No.1121403 

主　　题：nano-particle quantum size effect boundary condition effect size-dependent melting 

摘      要：The phonon thermal contribution to the melting temperature of nano-particles is inspected. The discrete summation of phonon states and its corresponding integration form as an approximation for a nano-particle or for a bulk system have been analyzed. The discrete phonon energy levels of pure size effect and the wave-vector shifts of boundary conditions are investigated in detail. Unlike in macroscopic thermodynamics, the integration volume of zero-mode of phonon for a nano-particle is not zero, and it plays an important role in pure size effect and boundary condition effect. We find that a nano-particle will have a rising melting temperature due to purely finite size effect; a lower melting temperature bound exists for a nano-particle in various environments, and the melting temperature of a nano-particle with free boundary condition reaches this lower bound. We suggest an easy procedure to estimation the melting temperature, in which the zero-mode contribution will be excluded, and only several bulk quantities will be used as input. We would like to emphasize that the quantum effect of discrete energy levels in nano-particles, which is not present in early thermodynamic studies on finite size corrections to melting temperature in small systems, should be included in future researches.