In recent experiments, external anisotropy has been a useful tool to tune different phases and study their competitions. In this paper, we look at the quantum Hall charge density wave states in the N = 2 Landau level. Without anisotropy, there are two first-order phase transitions between the Wigner crystal, the 2-electron bubble phase, and the stripe phase. By adding mass anisotropy, our analytical and numerical studies show that the 2-electron bubble phase disappears and the stripe phase significantly enlarges its domain in the phase diagram. Meanwhile, a regime of stripe crystals that may be observed experimentally is unveiled after the bubble phase gets out. Upon increase of the anisotropy, the energy of the phases at the transitions becomes progressively smooth as a function of the filling. We conclude that all first-order phase transitions are replaced by continuous phase transitions, providing a possible realisation of continuous quantum crystalline phase transitions.

在最近的实验中，外部各向异性已成为调整不同相位和研究它们的竞争的有用工具。在本文中，我们研究了N中的量子霍尔电荷密度波态 = 2 朗道级。在没有各向异性的情况下，维格纳晶体、2 电子气泡相和条纹相之间存在两个一级相变。通过添加质量各向异性，我们的分析和数值研究表明，2 电子气泡相消失，条纹相显着扩大了其在相图中的域。同时，在气泡相消失后，可以通过实验观察到的条纹晶体结构被揭开。随着各向异性的增加，转变处的相能量作为填充的函数逐渐变得平滑。我们得出结论，所有一阶相变都被连续相变取代，提供了连续量子晶体相变的可能实现。