title: Stacking Structures of Few-Layer Graphene Revealed by Phase-Sensitive Infrared Nanoscopy.
abstract: The stacking orders in few-layer graphene (FLG) strongly influences the electronic properties of the material. To explore the stacking-specific properties of FLG in detail, one needs powerful microscopy techniques that visualize stacking domains with sufficient spatial resolution. We demonstrate that infrared (IR) scattering scanning near-field optical microscopy (sSNOM) directly maps out the stacking domains of FLG with a nanometric resolution, based on the stacking-specific IR conductivities of FLG. The intensity and phase contrasts of sSNOM are compared with the sSNOM contrast model, which is based on the dipolar tip-sample coupling and the theoretical conductivity spectra of FLG, allowing a clear assignment of each FLG domain as Bernal, rhombohedral, or intermediate stacks for tri-, tetra-, and pentalayer graphene. The method offers 10-100 times better spatial resolution than the far-field Raman and infrared spectroscopic methods, yet it allows far more experimental flexibility than the scanning tunneling microscopy and electron microscopy.
authors.affiliation: †Department of Chemistry, Seoul National University, Seoul 136-701, Korea.
authors.forename: Deok-Soo
authors.initials: DS
authors.lastname: Kim
authors.affiliation: †Department of Chemistry, Seoul National University, Seoul 136-701, Korea.
authors.forename: Hyuksang
authors.initials: H
authors.lastname: Kwon
authors.affiliation: ‡CIC nanoGUNE Consolider, 20018 Donostia-San Sebastian, Spain.|§IKERBASQUE Basque Foundation for Science, 48011 Bilbao, Spain.
authors.forename: Alexey Yu
authors.initials: AY
authors.lastname: Nikitin
authors.affiliation: ∥Department of Physics and Astronomy, Seoul National University, Seoul 446-701, Korea.
authors.forename: Seongjin
authors.initials: S
authors.lastname: Ahn
authors.affiliation: ⊥Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martín-Moreno
authors.affiliation: #Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: García-Vidal
authors.affiliation: ∇Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Korea.
authors.forename: Sunmin
authors.initials: S
authors.lastname: Ryu
authors.affiliation: ∥Department of Physics and Astronomy, Seoul National University, Seoul 446-701, Korea.
authors.forename: Hongki
authors.initials: H
authors.lastname: Min
authors.affiliation: †Department of Chemistry, Seoul National University, Seoul 136-701, Korea.
authors.forename: Zee Hwan
authors.initials: ZH
authors.lastname: Kim
keywords: multilayer graphene; nanoplasmonics; nanoscopy; near-field optics; stacking orders