Observation of Plasmarons in Quasi-Freestanding Doped Graphene
Observation of Plasmarons in Quasi-Freestanding Doped Graphene
复制标题
DOI：
10.1126/science.1186489
复制
发表时间：
2010-05-21
期刊：
影响因子：
56.9
通讯作者：
Rotenberg, Eli
中科院分区：
文献类型：
--
作者：
Bostwick, Aaron;Speck, Florian;Rotenberg, Eli
石墨烯的一个特征是其不同寻常的圆锥形能带结构，导致在单个狄拉克交叉点上形成零能带隙。通过用角度分辨光电子能谱测量准自支撑石墨烯中载流子的光谱函数，我们发现在有限掺杂下，这一众所周知的线性狄拉克谱并不能完全描述载荷态的激发。我们观察到复合的“等离子激子”粒子，这是电荷载流子与等离子体的束缚状态，石墨烯电子气的密度振荡。狄拉克交叉点被分解为三个交叉点：第一个交叉点在纯电荷带之间，第二个交叉点在纯等离子激元带之间，第三个交叉点是电荷和等离子体激元带之间的环形交叉点。
A hallmark of graphene is its unusual conical band structure that leads to a zero-energy band gap at a single Dirac crossing point. By measuring the spectral function of charge carriers in quasi-freestanding graphene with angle-resolved photoemission spectroscopy, we showed that at finite doping, this well-known linear Dirac spectrum does not provide a full description of the charge-carrying excitations. We observed composite "plasmaron" particles, which are bound states of charge carriers with plasmons, the density oscillations of the graphene electron gas. The Dirac crossing point is resolved into three crossings: the first between pure charge bands, the second between pure plasmaron bands, and the third a ring-shaped crossing between charge and plasmaron bands.