Phonon drag thermopower and energy loss rate in single and bilayer graphene due to piezoelectric surface acoustic phonons in Bloch-Gruneisen regime
| Autor: | Meenhaz Ansari |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
Condensed matter physics Graphene Mean free path Phonon Relaxation (NMR) 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials law.invention Condensed Matter::Materials Science law 0103 physical sciences Condensed Matter::Strongly Correlated Electrons Wave vector 010306 general physics 0210 nano-technology Bilayer graphene Random phase approximation Phonon drag |
| Zdroj: | Physica E: Low-dimensional Systems and Nanostructures. 131:114722 |
| ISSN: | 1386-9477 |
| Popis: | In this report, we have both numerically and analytically calculated the phonon drag thermopower, S p z and, energy loss rate, F p z due to piezoelectric surface acoustic phonons present in the underlying piezoelectric substrate at a distance, d apart from single and bilayer graphene as a function of carrier's temperature, concentration and phonon mean free path . The numerical results are then reduced to analytical results in the Bloch-Gruneisen regime and the corresponding power dependency of the quantities described above are obtained. We have also included the effect of Thomas-Fermi and Random Phase Approximation screening into account in these calculations. The obtained unscreened results are further reduced in much simpler form for a particular case having no distance between the graphene samples and the underlying substrate or at larger values of distances. The temperature dependency in S p z and F p z for both SLG and BLG systems is found to be one order less than the in-plane acoustic phonons dependency, which is directly related to the matrix element of electron-in plane acoustic phonon interaction having a linear dependence on the phonon wave vector, q . Furthermore, a comparison of these calculations is made between the in-plane and piezoelectric surface acoustic phonon modes. One finds a crossover between these phonons modes depicting these are important in providing effective scattering channels for energy relaxation in typical experimental situations at different temperatures. |
| Databáze: | OpenAIRE |
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