论文标题

在均质电子流体的胶体相位

On the Colloidal Phase of the Homogeneous Electron Fluid

论文作者

Banks, Tom, Zhang, Bingnan

论文摘要

我们提供了半r性的论点,即均质电子流体(HEF)具有胶体相,将wigner晶体与高密度流体相分开。在晶体和流体基态能量之间的跨界界面附近,该参数对于晶体和更无定形相之间的任何量子过渡均相当一般并且有效。在这种状态下,胶体是凝胶,其“金石”模式是由晶体壁隔开的不规则流体液滴的流动。当流体的单个气泡跨越整个系统时,会发生金属绝缘子的过渡。除了这种过渡之外,胶体是溶胶,其特性取决于具有负表面张力的元稳定有限结晶石的存在。如果存在这些,则SOL相的能量低于均匀流体。在二维的HEF中,Kivelson和Spivak认为,至少以条纹的形式,这种负面的表面张力始终存在。我们认为,条纹的存在也意味着存在有限的负张力椭圆形的结晶石,并且很难计算有限的结晶石相和条纹相之间的详细竞争。我们还提供了较弱的论点,即有限的结晶石在三个维度中存在。这提供了我们声称的证据,即在\ cite {haule} \ cite {gapless}的数值计算中观察到的非零波数的无间隙激发是这些结晶岩(波斯型准晶状体)的量子残余物,它们在消失的表面张力的极限下。最后,我们建议对流体和SOL相之间的二阶量子相变的Landau平均场理论。

We provide semi-rigorous arguments that the Homogeneous Electron Fluid (HEF) has a colloidal phase separating the Wigner Crystal from the high density fluid phase. Near the crossover between crystal and fluid ground state energies, the argument is quite general and valid for practically any quantum transition between a crystal and a more amorphous phase. In this regime, the colloid is a gel and its "Goldstone" modes are flows of irregular fluid droplets separated by crystalline walls. A metal insulator transition occurs when a single bubble of fluid spans the entire system. Beyond this transition the colloid is a sol and its properties depend on the existence of meta-stable finite crystallites with negative surface tension. If these exist, the sol phase has lower energy than the homogeneous fluid. In the two dimensional HEF, Kivelson and Spivak argued that such negative surface tension objects always exist, at least in the form of stripes. We argue that the existence of stripes also implies the existence of finite negative tension elliptical crystallites and the detailed competition between the finite crystallite phase and striped phases is difficult to calculate. We also provide weaker arguments that finite crystallites exist in three dimensions. This provides evidence for our claim that the gapless excitations at non-zero wavenumber, observed in the numerical calculations of\cite{haule}\cite{gapless} are quantum remnants of these crystallites (Bosonic quasi-particles) in the limit of vanishing surface tension. Finally, we suggest a Landau mean field theory for the second order quantum phase transition between the fluid and sol phases.

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