Nanometric phonon spectroscopy for diamond and cubic boron nitride
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2021-11-05 |
| Journal | Physical review. B./Physical review. B |
| Authors | Jun Kikkawa, Takashi Taniguchi, Koji Kimoto |
| Institutions | National Institute for Materials Science, Japan Science and Technology Agency |
| Citations | 9 |
Abstract
Section titled āAbstractāLocal phonon properties near heterointerfaces or lattice defects are key for controlling various material properties such as thermal conductivity and thermoelectricity. However, high-spatial-resolution measurements of bulk phonons have hardly been established, even in typical nonpolar and polar bulk materials such as diamond and cubic boron nitride (c-BN), respectively. Here, we demonstrate nanometric measurements of phonon dispersions and mapping using a heterojunction of diamond and c-BN single crystals. To achieve high spatial/energy resolution, we use a monochromated (\ensuremath{\sim}20ā30 meV) electron nanoprobe, a high-sensitivity scintillator for counting inelastically scattered electrons, and the RichardsonāLucy deconvolution. The diamond phonon dispersion is first measured under a large-scattering-vector condition, particularly for the \ensuremath{\Gamma} point. Differential scattering cross sections of optical and acoustic-phonon modes in diamond and c-BN are also measured, and the totals of their modes are on the order of ${10}^{\ensuremath{-}5}\phantom{\rule{0.16em}{0ex}}\mathrm{n}{\mathrm{m}}^{2}$ for both crystals.