Gate induced monolayer behavior in twisted bilayer black phosphorus

Date
2017
Authors
Sevik, C.
Wallbank, J. R.
Gülseren, O.
Peeters, F. M.
Çakir, D.
Advisor
Instructor
Source Title
2D Materials
Print ISSN
2053-1583
Electronic ISSN
Publisher
IOP Publishing
Volume
4
Issue
3
Pages
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

Optical and electronic properties of black phosphorus strongly depend on the number of layers and type of stacking. Using first-principles calculations within the framework of density functional theory, we investigate the electronic properties of bilayer black phosphorus with an interlayer twist angle of 90°. These calculations are complemented with a simple k p model which is able to capture most of the low energy features and is valid for arbitrary twist angles. The electronic spectrum of 90° twisted bilayer black phosphorus is found to be x-y isotropic in contrast to the monolayer. However x-y anisotropy, and a partial return to monolayer-like behavior, particularly in the valence band, can be induced by an external out-of-plane electric field. Moreover, the preferred hole effective mass can be rotated by 90° simply by changing the direction of the applied electric field. In particular, a +0.4 (-0.4) V A-1 out-of-plane electric field results in a ~60% increase in the hole effective mass along the y (x) axis and enhances the my /mx (mx /my) ratio as much as by a factor of 40. Our DFT and k p simulations clearly indicate that the twist angle in combination with an appropriate gate voltage is a novel way to tune the electronic and optical properties of bilayer phosphorus and it gives us a new degree of freedom to engineer the properties of black phosphorus based devices. © 2017 IOP Publishing Ltd.

Course
Other identifiers
Book Title
Keywords
Black phosphorus, Effective mass, Electric field, First principles calculations, K.p
Citation
Published Version (Please cite this version)