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Anharmonic Phonons in Graphene from First Principles

Mordechai C. Kornbluth

Title:
Anharmonic Phonons in Graphene from First Principles
Author(s):
Kornbluth, Mordechai C.
Thesis Advisor(s):
Marianetti, Chris A.
Date:
Type:
Theses
Degree:
Ph.D., Columbia University
Department(s):
Applied Physics and Applied Mathematics
Persistent URL:
Abstract:
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.
Subject(s):
Condensed matter
Materials science
Physics
Graphene
Item views
46
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Suggested Citation:
Mordechai C. Kornbluth, , Anharmonic Phonons in Graphene from First Principles, Columbia University Academic Commons, .

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