Overdoping Graphene Beyond the van Hove Singularity

被引：108

作者：

Rosenzweig, Philipp ^{[1
]}

Karakachian, Hrag ^{[1
]}

Marchenko, Dmitry ^{[2
]}

Kuester, Kathrin ^{[1
]}

Starke, Ulrich ^{[1
]}

机构：

[1] Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany

[2] Helmholtz Zentrum Berlin Mat & Energie, Elektronenspeicherring BESSY II, Albert Einstein Str 15, D-12489 Berlin, Germany

来源：

PHYSICAL REVIEW LETTERS | 2020年 / 125卷 / 17期

关键词：

MAGIC-ANGLE; ELECTRON INTERACTIONS; FERMI-SURFACE; GROUND-STATE; SUPERCONDUCTIVITY; ENERGY; SYSTEM; GAS;

D O I：

10.1103/PhysRevLett.125.176403

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

At very high doping levels the van Hove singularity in the pi* 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 pi* van Hove singularity, up to a charge carrier density of 5.5 x 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.

引用

页数：6

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