• 文献标题:   Valley precession in graphene superlattices
  • 文献类型:   Article
  • 作  者:   WANG SK, WANG J
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   1098-0121 EI 1550-235X
  • 通讯作者地址:   Southeast Univ
  • 被引频次:   17
  • DOI:   10.1103/PhysRevB.92.075419
  • 出版年:   2015

▎ 摘  要

One of the challenges in valleytronics is how to effectively manipulate the valley degree of freedom of electrons in graphene. We propose to use a pseudovalley exchange field to rotate the valley, which arises in a graphene superlattice (GS) structure due to the two inequivalent K and K' valleys folded and coupled together. The valley is shown to precess periodically in real space, but the precession itself has a spatial anisotropy unless the GS structure still possesses a rotational symmetry. The pseudovalley exchange field exclusively determines the valley precession periodicity when the electron energy is much larger than the possible GS energy gap. Our findings provide a practical way to control and manipulate the valley degree of freedom in graphene.