论文标题
Quadriexcitons和对称电子孔双层中的激素冷凝物与山谷退化
Quadriexcitons and excitonic condensate in a symmetric electron-hole bilayer with valley degeneracy
论文作者
论文摘要
使用量子蒙特卡洛模拟，我们绘制了具有双重山谷变性的对称电子孔双层的零温度相图，作为Interlayer距离$ d $和内层密度$ n $的功能。我们发现，山谷退化的效果是缩小兴奋子冷凝物的稳定性区域，以小$ d $为小$ d $的Quadriexcitons和大$ d $的四组分等离子体的Quadriexcitons，对兴奋子冷凝水分的价值略有影响。密度窗口中冷凝物的外壳可能解释了为什么仅观察到凝码双层中两个有限载体密度的有限值，因此仅观察到被解释为冷凝的特征。我们的相图可能会提供指示以选择设备参数以供将来实验。
Using quantum Monte Carlo simulations we have mapped out the zero temperature phase diagram of a symmetric electron-hole bilayer with twofold valley degeneracy, as function of the interlayer distance $d$ and in-layer density $n$. We find that the effect of the valley degeneracy is to shrink the region of stability of the excitonic condensate, in favor of quadriexcitons at small $d$ and of the four-component plasma at large $d$, with minor effects on the value of the excitonic condensate fraction. The enclosure of the condensate in a density window possibly explains why anomalous tunnelling conductivity, interpreted as signature of condensation, is observed only between two finite values of carrier density in graphene bilayers. Our phase diagram may provide directions to select device parameters for future experiments.
