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arXiv · 1412.1956

Can nano-particle melt below the melting temperature of its free surface partner?

Xiao-Hong Sui·Zongguo Wang·Kai Kang·Shaojing Qin·Chuilin Wang
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Abstract

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 were 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 found 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 was not present in early thermodynamic studies on finite size corrections to melting temperature in small systems, should be included in future researches.

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Xiao-Hong Sui, Zongguo Wang, Kai Kang, Shaojing Qin, Chuilin Wang. 2014-12-05. Can nano-particle melt below the melting temperature of its free surface partner?. https://doi.org/10.1088/0253-6102%2F63%2F2%2F19

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