title: Helical states of topological insulator Bi₂Se₃.
abstract: We report density functional theory analysis of the electronic and quantum transport properties of Bi(2)Se(3) topological insulator, focusing on the helical surface states at the Fermi level E(F). The calculated Dirac point and the tilt angle of the electron spin in the helical states are compared quantitatively with the experimental data. The calculated conductance near E(F) shows a V-shaped spectrum, consistent with STM measurements. The spins in the helical states at E(F) not only tilts out of the two-dimensional plane, they also oscillate with a 3-fold symmetry going around the two-dimensional Brillouin zone. The helical states penetrate into the material bulk, where the first quintuple layer contributes 70% of the helical wave functions.
authors.affiliation: Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada. yhzhao@sicnu.edu.cn
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yibin
authors.initials: Y
authors.lastname: Hu
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhu
authors.forename: Hong
authors.initials: H
authors.lastname: Guo