title: Raman spectra of few-layer phosphorene studied from first-principles calculations.
abstract: Raman spectra of few-layer phosphorene have been systematically studied using density functional theory calculations. We find that due to the interlayer van der Waals interactions, the low-frequency rigid layer Ag breathing mode and B1g shear mode can shift by as much as 45.1 cm(-1) and 38.5 cm(-1), respectively, as the layer numbers increase from 2L to 5L. In addition, a typical characteristic for the experimentally observable [Formula: see text] mode (~460 cm(-1) in bulk) is identified. Interestingly, this mode changes from coupled in-plane and out-of-plane vibrations in single layer to pure in-plane vibrations in a few layers and the corresponding frequencies vary by as much as over 10 cm(-1). We argue that this Raman frequency variation might be used to experimentally characterize the thickness of this intriguing 2D layered material.
authors.affiliation: Department of Physics and National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Feng
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.forename: Yongping
authors.initials: Y
authors.lastname: Du
authors.forename: Feng
authors.initials: F
authors.lastname: Miao
authors.forename: Chun-Gang
authors.initials: CG
authors.lastname: Duan
authors.forename: Baigeng
authors.initials: B
authors.lastname: Wang
authors.forename: Xiangang
authors.initials: X
authors.lastname: Wan