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Two-dimensional Phonon Polaritons in Multilayers of Hexagonal Boron Nitride from a Macroscopic Phonon Model by Zhang, Jian-zhong is a scholarly article available to read on EtoBox.

What is Two-dimensional Phonon Polaritons in Multilayers of Hexagonal Boron Nitride from a Macroscopic Phonon Model about?

Phonon polaritons (PhPs) in freestanding and supported multilayers (MuLs) of hexagonal boron nitride (hBN) are systematically studied using a macroscopic optical-phonon model. The PhP properties such as confinement, group velocity, propagation quality factor (PQF) and wavelength scaling are studied. Owing to the nonlocal high-frequency screening, there is an upper frequency limit making the two-dimensional (2D) PhPs have a frequency band, and also a maximum PQF occurs near the centre frequency. The substrate's dielectric response should be included to accurately calculate the PhP properties. While the simple electrostatic approximation (ESA) is a proper treatment for PhP frequencies $\omega$ above $\omega_0$ (e.g. $\omega>1.03\omega_0$ for the 30-layers; $\omega_0$ is the $\Gamma$ point optical phonon frequency), it fails to describe the PhP properties near $\omega_0$ and the effect of retardation should be included for an accurate description. The PhP wavelength versus the layer thickness near $\omega_0$ deviates significantly from a linear scaling law given by the ESA due to strong phonon-photon coupling. The calculated PhP dispersion, PQF and scaling are compared with experiment

Author

Zhang, Jian-zhong

Published

2021

Language

EN