Coherent acoustic phonons in a coupled hexagonal boron nitride-graphite heterostructure
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In: Structural Dynamics Volume 11 / Issue 1 (2024-02-14) , S. ; eissn:2329-7778
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Femtosecond optically excited coherent acoustic phonon modes (CAPs) are investigated in a free-standing van der Waals heterostructure composed of a 20-nm transparent hexagonal boron nitride (hBN) and a 42-nm opaque graphite layer. Employing ultrafast electron diffraction, which allows for the independent evaluation of strain dynamics in the constituent material layers, three different CAP modes are identified within the bilayer stack after the optical excitation of the graphite layer. An analytical model is used to discuss the creation of individual CAP modes. Furthermore, their excitation mechanisms in the heterostructure are inferred from the relative phases of these modes by comparison with a numerical linear-chain model. The results support an ultrafast heat transfer mechanism from graphite to the hBN lattice system, which is important to consider when using this material combination in devices.
@article{doi:10.17170/kobra-202403269871,
author ={Ungeheuer, Arne and Bach, Nora and Mir, Mashood Tariq and Hassanien, Ahmed Shehata and Nöding, Lukas and Baumert, Thomas and Schäfer, Sascha and Senftleben, Arne},
title ={Coherent acoustic phonons in a coupled hexagonal boron nitride-graphite heterostructure},
keywords ={530 and Phonon and Halbleiter and Optische Eigenschaft and Elektronenbeugung and Wärmeübertragung and Heterostruktur},
copyright ={http://creativecommons.org/licenses/by/4.0/},
language ={en},
journal ={Structural Dynamics},
year ={2024-02-14}
}