title: Anisotropic quantum confinement effect and electric control of surface states in Dirac semimetal nanostructures.
abstract: The recent discovery of Dirac semimetals represents a new achievement in our fundamental understanding of topological states of matter. Due to their topological surface states, high mobility, and exotic properties associated with bulk Dirac points, these new materials have attracted significant attention and are believed to hold great promise for fabricating novel topological devices. For nanoscale device applications, effects from finite size usually play an important role. In this report, we theoretically investigate the electronic properties of Dirac semimetal nanostructures. Quantum confinement generally opens a bulk band gap at the Dirac points. We find that confinement along different directions shows strong anisotropic effects. In particular, the gap due to confinement along vertical c-axis shows a periodic modulation, which is absent for confinement along horizontal directions. We demonstrate that the topological surface states could be controlled by lateral electrostatic gating. It is possible to generate Rashba-like spin splitting for the surface states and to shift them relative to the confinement-induced bulk gap. These results will not only facilitate our fundamental understanding of Dirac semimetal nanostructures, but also provide useful guidance for designing all-electrical topological spintronics devices.
authors.affiliation: School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China.
authors.forename: Xianbo
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore.
authors.forename: Shengyuan A
authors.initials: SA
authors.lastname: Yang
authors.affiliation: School of Basic Science, East China Jiaotong University, Nanchang 330013, China.
authors.forename: Zhengfang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China.
authors.forename: Huili
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Zhou