Anharmonic Phonons in Graphene from First Principles
- Anharmonic Phonons in Graphene from First Principles
- Kornbluth, Mordechai C.
- Thesis Advisor(s):
- Marianetti, Chris A.
- Ph.D., Columbia University
- Applied Physics and Applied Mathematics
- Persistent URL:
- In this work, we develop a new flexible formalism to calculate anharmonic interatomic interactions from first principles at arbitrary order. Using the recently-developed slave-mode basis, we Taylor-expand the potential with a minimal number of independent coefficients. The anharmonic dynamical tensor, a higher-order generalization of the dynamical matrix in strain+reciprocal space, is calculated via a generalized frozen phonon methodology. We perform high-throughput calculations, emphasizing efficiency with multidimensional finite differences and Hellman-Feynman forces. Applying the methodology to graphene, we show convergence through fifth order terms. Our calculated force constants produce stress-strain curves, bond-length relaxations, and phonon spectra that agree well with those expected within DFT. We show that to fully capture anharmonic effects, long-range interactions must be included.
- Condensed matter
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- Suggested Citation:
- Mordechai C. Kornbluth, 2017, Anharmonic Phonons in Graphene from First Principles, Columbia University Academic Commons, https://doi.org/10.7916/D8708CRN.