title: Role of Interlayer Coupling on the Evolution of Band Edges in Few-Layer Phosphorene.
abstract: Using first-principles calculations, we have investigated the evolution of band edges in few-layer phosphorene as a function of the number of P layers. Our results predict that monolayer phosphorene is an indirect band gap semiconductor and its valence band edge is extremely sensitive to strain. Its band gap could undergo an indirect-to-direct transition under a lattice expansion as small as 1% along the zigzag direction. A semiempirical interlayer coupling model is proposed, which can reproduce the evolution of valence band edges obtained by first-principles calculations well. We conclude that the interlayer coupling plays a dominant role in the evolution of the band edges via decreasing both band gap and carrier effective masses with the increase of phosphorene thickness. Scrutiny of the orbital-decomposed band structure provides a better understanding of the upward shift of the valence band maximum, surpassing that of the conduction band minimum.
authors.affiliation: Department of Applied Physics, Xi'an University of Technology , Xi'an 710054, China.
authors.forename: V
authors.initials: V
authors.lastname: Wang
authors.affiliation: Department of Applied Physics, Xi'an University of Technology , Xi'an 710054, China.|Department of Applied Physics, Xi'an Jiaotong University , Xi'an 710049, China.
authors.forename: Y C
authors.initials: YC
authors.lastname: Liu
authors.affiliation: New Industry Creation Hatchery Center, Tohoku University , Sendai, Miyagi 980-8579, Japan.|Kutateladze Institute of Thermophysics, Siberian Branch of Russian Academy of Sciences , Novosibirsk 630090, Russia.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawazoe
authors.affiliation: School of Materials Science & Engineering, University of Science and Technology Beijing , Beijing 100083, China.
authors.forename: W T
authors.initials: WT
authors.lastname: Geng
keywords: first-principles calculations; orbital-decomposed band structure; phosphorene; semiempirical interlayer coupling