论文标题
硬盘系统的全球状态和相变
Global equation of state and phase transitions of the hard disc systems
论文作者
论文摘要
硬盘系统在二维事务的研究中起着基本作用[1-3]。已经报道了所有阶段和相变区域的计算机模拟的高精度可压缩性数据[4-15]。特别是，伯纳德（Bernard）和克劳斯（Thys。Rev.Lett。，107，155704，2011）[10]显示了具有模拟结果的硬盘系统相变的完整而准确的图片。但是，对系统的彻底描述取决于整个密度范围内状态（EO）的分析方程。尽管发布的大多数EOS仅适用于稳定的流体区域[1,16]，但很少有液态 - 六型过渡区域（Phys。Phys。Rev。Lett。，11，241，1963 [17];Phys。E.63，042201，2001，2001 [18]; 74，061106，2006 [19] [19]）。当前可用的所有EO都无法对相变的定量描述。在这里，我们构建了一个简单的EOS，以重现所有稳定液体，液体 - 效应过渡区域和六角形相的高精度仿真数据。然后，当新的EO与固相的EOS平滑地结合在一起时，将获得全球EO。使用这个全局方程式，我们能够准确地识别从稳定液体到示象的所有相和相变，然后再转变为固体阶段。发现液体效应的过渡是弱的一阶，即密度不连续的，而gibbs自由能在熵和Helmholtz自由能中连续连续。六角固化的转变是连续的高阶相变。
The hard disc system plays a fundamental role in the study of two-dimensional matters [1-3]. High-precision compressibility data from computer simulations have been reported for all the phases and phase transition regions [4-15]. In particular, Bernard and Krauth (Phys. Rev. Lett., 107, 155704, 2011) [10] presented a complete and accurate picture of the phase transitions of the hard disc system with simulation results. However, thorough descriptions of the system depend on analytical equations of state (EoS) over the entire density range. While majority of EoS published are for the stable fluid region only [1,16], few attempted the liquid-hexact transition region (Phys. Rev. Lett., 11, 241, 1963 [17]; Phys. Rev. E. 63, 042201, 2001 [18]; 74, 061106, 2006 [19]). All the EoS currently available are incapable of quantitative descriptions of the phase transitions. Here we construct a simple EoS to reproduce high-precision simulation data for all the stable liquid, liquid-hexatic transition region and hexatic phase. A global EoS is then obtained when the new EoS is smoothly united with a revisited EoS for the solid phase. Using this global equation, we are able to accurately identify all the phases and the phase transitions from the stable liquid to hexatic, then to solid phases. The liquid-hexatic transition is found to be of weak first-order, namely discontinuous in density and the Gibbs free energy while continuous in entropy and the Helmholtz free energy. The hexatic-solid transition is a continuous high-order phase transition.
