论文标题
超越范霍夫奇异性的土地烯
Overdoping graphene beyond the van Hove singularity
论文作者
论文摘要
在非常高的兴奋剂水平下，$π^*$的石墨烯带中的van hove奇异性被占据，外来地面状态可能会出现，这是由多体相互作用驱动的。通过ytterbium Intercalation和钾吸附的组合，We $ n $ dope Espistagial石墨烯在硅碳化物上超过了$π^*$ van hove singularity，最多可达5.5 $ \ times $ 10 $^^{14} $ CM $ cm $^{-2} $ 5.5 $ \ times $ 10 $^{-2} $。该机制标志着LIFSHITZ过渡的明确完成，其中Fermi表面拓扑已从两个电子口袋演变为一个巨大的孔口袋。角度分辨的光电子光谱证实了这些变化是由电子结构重新构化而不是刚性带移驱动的。我们的结果在外延石墨烯的相图中打开了以前无法达到的超越货物状态，从而在该原型二维材料中访问了潜在的外来相位的未开发的景观。
At very high doping levels the van Hove singularity in the $π^*$ band of graphene becomes occupied and exotic ground states possibly emerge, driven by many-body interactions. Employing a combination of ytterbium intercalation and potassium adsorption, we $n$ dope epitaxial graphene on silicon carbide past the $π^*$ van Hove singularity, up to a charge carrier density of 5.5$\times$10$^{14}$ cm$^{-2}$. This regime marks the unambiguous completion of a Lifshitz transition in which the Fermi surface topology has evolved from two electron pockets into a giant hole pocket. Angle-resolved photoelectron spectroscopy confirms these changes to be driven by electronic structure renormalizations rather than a rigid band shift. Our results open up the previously unreachable beyond-van-Hove regime in the phase diagram of epitaxial graphene, thereby accessing an unexplored landscape of potential exotic phases in this prototype two-dimensional material.
