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MELTING of COPPER with E. Polturak and A. Kanigel

  1. CRYSTAL MELTS WHEN: 

  2. MOTIVATION: Understanding experimental data of Polturak et al on role of point defects in the melting of solid helium. Copper was selected to avoid the complications of modeling a quantum solid.

  3. OBSERVATION: Expansion of the sample might begin near the surface where the formation energies of defects are lower.

  4. EMIL's CONJECTURE: Instability leading to melting occured once the molar volume reached a critical value (equal to the molar volume of the liquid phase) independent of the path(defects or vacancies) to the increase.

  5. RESULTS: For copper samples with periodic boundary conditions, Amit Kanigel, Emil Polturak and JA found this was true and also that self-interstitials, rather than vacancies were the important defects. They showed that Born's melting criterion is valid for the mechanical melting that occurs when melting from a surface or a grain boundary is artificially supressed.

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