title: Indirect-direct band gap transition through electric tuning in bilayer MoS2.
abstract: We investigate the electronic properties of bilayer MoS2 exposed to an external electric field by using first-principles calculations. It is found that a larger interlayer distance, referring to that by standard density functional theory (DFT) with respect to that by DFT with empirical dispersion corrections, makes indirect-direct band gap transition possible by electric control. We show that external electric field effectively manipulates the valence band contrast between the K- and Γ-valleys by forming built-in electric dipole fields, which realizes an indirect-direct transition before a semiconductor-metal transition happens. Our results provide a novel efficient access to tune the electronic properties of two-dimensional layered materials.
authors.affiliation: Key laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730 000, China.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Zhang
authors.affiliation: Key laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730 000, China.
authors.forename: M S
authors.initials: MS
authors.lastname: Si
authors.affiliation: Key laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730 000, China.
authors.forename: Y H
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Key laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730 000, China.
authors.forename: X P
authors.initials: XP
authors.lastname: Gao
authors.affiliation: Graphene Research Institute, Sejong University, Seoul 143 747, Korea.
authors.forename: Dongchul
authors.initials: D
authors.lastname: Sung
authors.affiliation: Graphene Research Institute, Sejong University, Seoul 143 747, Korea.
authors.forename: Suklyun
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Physics, Xiangtan University, Hunan 411 105, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: He