Comparing the phonons and vibrations in carbon allotropes with neutron spectroscopy: Microdiamond, few-layer graphene, and amorphous fibers
Abstract
Powder-averaged inelastic neutron spectroscopy was performed in order to compare the phonons of microdiamond, few-layer graphene, and amorphous carbon fibers at room temperature. Both acoustic and optical phonons were observed in the crystalline allotropes. We present average group velocities, phonon densities of states, and heat capacities relevant to intrinsic thermal transport. High-temperature measurements were performed to evaluate whether quasiparticle broadening from phonon–phonon scattering could be detected. The glassy carbon form in the fibers exhibits pronounced spectral broadening and an enhanced low-energy density of states beyond the Debye prediction. Methods for estimating thermal conductivity using inelastic neutron data as input to the phonon-gas model are discussed. We highlight opportunities and challenges for employing higher-resolution methods to directly determine phonon lifetimes.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (10)
Md. Rezoanur Rahman
Institute for Superconducting and Electronic Materials, University of Wollongong 1 , Wollongong, New South Wales 2500,
Caleb Stamper
Institute for Superconducting and Electronic Materials
Kyle A. Portwin
Institute for Superconducting and Electronic Materials, University of Wollongong 1 , Wollongong, New South Wales 2500,
Xiaolin Wang
School of Pharmacy and State Key Laboratory of Quality Research in Chinese Medicine
Richard A. Mole
Australian Nuclear Science Technology Organisation
Pablo Galaviz
Australian Nuclear Science Technology Organisation
Aiswarya Pradeepkumar
School of Electrical and Data Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney 5 , Sydney, New South Wales 2007,
Kirrily C. Rule
Dehong Yu
Australian Nuclear Science and Technology Organisation
David L. Cortie
Institute for Superconducting and Electronic Materials, University of Wollongong 1 , Wollongong, New South Wales 2500,