Gate-induced gap in bilayer graphene suppressed by Coulomb repulsion
Gate-induced gap in bilayer graphene suppressed by Coulomb repulsion
复制标题
库仑斥力抑制双层石墨烯中栅极引起的间隙
DOI：
10.1103/physrevb.93.035109
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发表时间：
2016-01
影响因子：
3.7
通讯作者：
Zhang Yu-Zhong
中科院分区：
文献类型：
--
作者：
Xu Jin-Rong;Song Ze-Yi;Lin Hai-Qing;Zhang Yu-Zhong
我们基于离子双层哈伯德模型，通过在顺磁态下采用相干势近似，研究了现场库仑斥力 $U$ 对电门控双层石墨烯带隙的影响。我们发现，虽然现场库仑斥力 $U$ 或外部垂直电场 $E$ 单独都会有利于双层石墨烯中的带隙状态，但它们之间的竞争将令人惊讶地导致带隙幅度的抑制。我们的结果可用于理解光学和传输测量报告的间隙尺寸的差异，以及在角分辨光电发射光谱研究中观察到的令人费解的特征。
We investigate the effect of on-site Coulomb repulsion $U$ on the band gap of the electrically gated bilayer graphene by employing coherent potential approximation in the paramagnetic state, based on an ionic two-layer Hubbard model. We find that, while either the on-site Coulomb repulsion $U$ or the external perpendicular electric field $E$ alone will favor a gapped state in the bilayer graphene, competition between them will surprisingly lead to a suppression of the gap amplitude. Our results can be applied to understand the discrepancies of gap size reported from optical and transport measurements, as well as the puzzling features observed in angular resolved photoemission spectroscopic study.