Wigner crystallization at large fine structure constant
Wigner crystallization at large fine structure constant
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DOI：
10.1103/physrevb.106.l041402
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发表时间：
2021-10
期刊：
影响因子：
--
通讯作者：
S. Joy;B. Skinner
中科院分区：
文献类型：
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作者：
S. Joy;B. Skinner
当有效精细结构常数α增加时，我们考虑了二维大质量狄拉克电子系统中维格纳晶态的命运。在狄拉克系统中，较大的α值天真地对应于较强的电子-电子相互作用，但它也意味着较强的带间介电响应，从而有效地使电子电荷重新正规化。我们用两种独立的方法计算了与Wigner晶态的量子和热熔化相关的临界密度和临界温度。结果表明，在α1$时，Wigner晶态可以用对数相互作用电子来最好地理解，并且临界密度和熔化温度都接近一个与α无关的普适值。我们结合最近在魔角附近扭曲的双层石墨烯的实验讨论了我们的结果。
We consider the fate of the Wigner crystal state in a two dimensional system of massive Dirac electrons as the effective fine structure constant $\alpha$ is increased. In a Dirac system, larger $\alpha$ naively corresponds to stronger electron-electron interactions, but it also implies a stronger interband dielectric response that effectively renormalizes the electron charge. We calculate the critical density and critical temperature associated with quantum and thermal melting of the Wigner crystal state using two independent approaches. We show that at $\alpha \gg 1$, the Wigner crystal state is best understood in terms of logarithmically-interacting electrons, and that both the critical density and the melting temperature approach a universal, $\alpha$-independent value. We discuss our results in the context of recent experiments in twisted bilayer graphene near the magic angle.