Department of Physics, MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Auckland, Auckland 1142, New Zealand.
School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia.
J Chem Phys. 2019 Mar 7;150(9):094705. doi: 10.1063/1.5086435.
We consider the surface melting of metal nanowires by solving a phenomenological two-parabola Landau model and by conducting molecular dynamics simulations of nickel and aluminum nanowires. The model suggests that surface melting will precede bulk melting when the melt completely wets the surface and the wire is sufficiently thick, as is the case for planar surfaces and sufficiently large nanoparticles. Surface melting does not occur if the melt partially wets or does not wet the surface. We test this model, which assumes that the surface energies of the wire are isotropic, using molecular dynamics simulations. For nickel, we observe the onset of anisotropic surface melting associated with each of the two surface facets present, but this gives way to uniform surface melting and the solid melts radially until the solid core eventually breaks up. For aluminum, while we observe complete surface melting of one facet, the lowest energy surface remains partially dry even up to the point where the melt completely penetrates the solid core.
我们通过求解一个唯象的双抛物线朗道模型并对镍和铝纳米线进行分子动力学模拟来研究金属纳米线的表面熔化。该模型表明，当熔体液完全润湿表面且纳米线足够厚时（对于平面表面和足够大的纳米颗粒而言），表面熔化将先于体熔化发生。如果熔体液部分润湿或不润湿表面，则不会发生表面熔化。我们使用分子动力学模拟来测试该模型，该模型假设纳米线的表面能各向同性。对于镍，我们观察到与存在的两个表面面之一相关的各向异性表面熔化的开始，但这会让位于均匀的表面熔化，并且固体径向熔化，直到固体核心最终破裂。对于铝，尽管我们观察到一个面完全熔化，但最低能量的表面即使在熔体液完全穿透固体核心时仍部分干燥。
