Tsiok E N, Gaiduk E A, Fomin Yu D, Ryzhov V N
Vereshchagin Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk 108840, Moscow, Russia.
Soft Matter. 2020 Apr 29;16(16):3962-3972. doi: 10.1039/c9sm02262g.
We present a molecular dynamics simulation study of the phase diagram and melting scenarios of two-dimensional Hertzian spheres with exponent 7/2. We have found multiple re-entrant melting of a single crystal with a triangular lattice in a wide range of densities from 0.5 to 10.0. Depending on the position on the phase diagram, the triangular crystal has been shown to melt through both two-stage melting with a first-order hexatic-isotropic liquid transition and a continuous solid-hexatic transition as well as in accordance with the Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young (BKTHNY) scenario (two continuous transitions with an intermediate hexatic phase). We studied the behavior of heat capacity and have shown that despite two-stage melting, the heat capacity has one peak which seems to correspond to a solid-hexatic transition.
我们展示了一项关于指数为7/2的二维赫兹球体的相图和熔化情况的分子动力学模拟研究。我们发现在0.5至10.0的广泛密度范围内，具有三角晶格的单晶会发生多次再入熔化。根据相图上的位置，三角晶体已被证明通过具有一级六方各向同性液体转变的两阶段熔化以及连续的固-六方转变而熔化，并且符合贝雷津斯基-科斯特利茨- Thouless-哈珀林-尼尔森-杨（BKTHNY）情景（两个连续转变，中间有一个六方相）。我们研究了热容量的行为，并表明尽管有两阶段熔化，但热容量有一个峰值，这似乎对应于固-六方转变。
