title: Tunable phonon polaritons in atomically thin van der Waals crystals of boron nitride.
abstract: van der Waals heterostructures assembled from atomically thin crystalline layers of diverse two-dimensional solids are emerging as a new paradigm in the physics of materials. We used infrared nanoimaging to study the properties of surface phonon polaritons in a representative van der Waals crystal, hexagonal boron nitride. We launched, detected, and imaged the polaritonic waves in real space and altered their wavelength by varying the number of crystal layers in our specimens. The measured dispersion of polaritonic waves was shown to be governed by the crystal thickness according to a scaling law that persists down to a few atomic layers. Our results are likely to hold true in other polar van der Waals crystals and may lead to new functionalities.
authors.affiliation: Department of Physics, University of California, San Diego (UCSD), La Jolla, CA 92093, USA.
authors.forename: S
authors.initials: S
authors.lastname: Dai
authors.forename: Z
authors.initials: Z
authors.lastname: Fei
authors.forename: Q
authors.initials: Q
authors.lastname: Ma
authors.forename: A S
authors.initials: AS
authors.lastname: Rodin
authors.forename: M
authors.initials: M
authors.lastname: Wagner
authors.forename: A S
authors.initials: AS
authors.lastname: McLeod
authors.forename: M K
authors.initials: MK
authors.lastname: Liu
authors.forename: W
authors.initials: W
authors.lastname: Gannett
authors.forename: W
authors.initials: W
authors.lastname: Regan
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: M
authors.initials: M
authors.lastname: Thiemens
authors.forename: G
authors.initials: G
authors.lastname: Dominguez
authors.forename: A H
authors.initials: AH
authors.lastname: Castro Neto
authors.forename: A
authors.initials: A
authors.lastname: Zettl
authors.forename: F
authors.initials: F
authors.lastname: Keilmann
authors.forename: P
authors.initials: P
authors.lastname: Jarillo-Herrero
authors.forename: M M
authors.initials: MM
authors.lastname: Fogler
authors.forename: D N
authors.initials: DN
authors.lastname: Basov