Song Jizhe, Zhang Zhongyuan, Feng Naixing, Wang Jingang
College of Science, Liaoning Petrochemical University, Fushun 113001, China.
Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
Nanomaterials (Basel). 2021 Sep 18;11(9):2433. doi: 10.3390/nano11092433.
In this work, we investigate the role of an external electric field in modulating the spectrum and electronic structure behavior of twisted bilayer graphene (TBG) and its physical mechanisms. Through theoretical studies, it is found that the external electric field can drive the relative positions of the conduction band and valence band to some extent. The difference of electric field strength and direction can reduce the original conduction band, and through the Fermi energy level, the band is significantly influenced by the tunable electric field and also increases the density of states of the valence band passing through the Fermi level. Under these two effects, the valence and conduction bands can alternately fold, causing drastic changes in spectrum behavior. In turn, the plasmon spectrum of TBG varies from semiconductor to metal. The dielectric function of TBG can exhibit plasmon resonance in a certain range of infrared.
在这项工作中，我们研究了外部电场在调制扭曲双层石墨烯（TBG）的光谱和电子结构行为及其物理机制方面的作用。通过理论研究发现，外部电场在一定程度上可以驱动导带和价带的相对位置。电场强度和方向的差异可以降低原始导带，并且通过费米能级，能带受到可调电场的显著影响，同时也增加了穿过费米能级的价带的态密度。在这两种效应下，价带和导带可以交替折叠，导致光谱行为发生剧烈变化。反过来，TBG的等离激元光谱从半导体变为金属。TBG的介电函数可以在一定范围的红外波段表现出等离激元共振。
