石墨烯量子磁输运性质的电场效应

Electrostatic field effect on the magnetotransport property in graphene

最近研究发现石墨烯在一维周期性电学或磁学调制势下,其扩散电导率会出现Weiss振荡.本文进一步探索了面外加垂直磁场和面内加横向电场以及一维周期性弱调制电学势的多场耦合作用下,石墨烯的量子磁输运性质,结果表明:Weiss振荡振幅和电导率数值都随着静电场的增加而增加.有趣的是,当电场与磁场的比值达到某一临界值,即β_1=E/(ν_F·B)=1时,输运电导率的Weiss振荡突然消失.这一奇特现象在传统的二维电子气体中是不存在的,因此可以归因于石墨烯载流子外加电磁场的反常相对论性能谱.

Recent theoretical works have predicated the appearance of Weiss oscillations in the magnetoconductivity with a one - dimensional periodic electrical or magnetic modulation in graphene. We further explore the quantum transport of Dirae electrons in graphene sheet in the presence of a perpendicular electric field that is weakly and periodically modulated along one direction. We find that both the oscillation amplitude （OA） of Weiss oscillation and the value of conductivity increase with the increasing electric field E. We also find that the electric field leads the Weiss oscillation todisappear when the value of electric to magnetic field ratio approaches a threshold value, i. e. , β1=E/（vF·B）=1 These phenomena are a consequence of the anomalous spectrum of electron in graphene.