title: Edge phonons in black phosphorus.
abstract: Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil.
authors.forename: H B
authors.initials: HB
authors.lastname: Ribeiro
authors.affiliation: Instituto de Física Teórica, Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), 01140-070 São Paulo, Brazil.
authors.forename: C E P
authors.initials: CE
authors.lastname: Villegas
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil.
authors.forename: D A
authors.initials: DA
authors.lastname: Bahamon
authors.affiliation: Instituto de Física Gleb Wataghin (IFGW), Universidade Estadual de Campinas, 13083-970 Campinas, Brazil.
authors.forename: D
authors.identifier: 0000-0002-4530-4265
authors.initials: D
authors.lastname: Muraca
authors.affiliation: Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.
authors.forename: A H
authors.initials: AH
authors.lastname: Castro Neto
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil.
authors.forename: E A T
authors.initials: EA
authors.lastname: de Souza
authors.affiliation: Instituto de Física Teórica, Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), 01140-070 São Paulo, Brazil.
authors.forename: A R
authors.initials: AR
authors.lastname: Rocha
authors.affiliation: Departamento de Física, Universidade Federal de Minas Gerais (UFMG), 30161-970 Belo Horizonte, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Pimenta
authors.affiliation: MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil.
authors.forename: C J S
authors.initials: CJ
authors.lastname: de Matos