Lattice dynamics and electron-phonon coupling calculations using non-diagonal supercells
Physical Review B
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Lloyd-Williams, J., & Monserrat Sanchez, B. (2015). Lattice dynamics and electron-phonon coupling calculations using non-diagonal supercells. Physical Review B, 92 (184301)https://doi.org/10.1103/PhysRevB.92.184301
We study the direct calculation of total energy derivatives for lattice dynamics and electronphonon coupling calculations using supercell matrices with non-zero off-diagonal elements. We show that it is possible to determine the response of a periodic system to a perturbation characterized by a wave vector with reduced fractional coordinates (m₁/n₁, m₂/n₂, m₃/n₃) using a supercell containing a number of primitive cells equal to the least common multiple of n₁, n₂, and n₃. If only diagonal supercell matrices are used, a supercell containing n₁n₂n₃ primitive cells is required. We demonstrate that the use of non-diagonal supercells significantly reduces the computational cost of obtaining converged zero-point energies and phonon dispersions for diamond and graphite. We also perform electron-phonon coupling calculations using the direct method to sample the vibrational Brillouin zone with grids of unprecedented size, which enables us to investigate the convergence of the zero-point renormalization to the thermal and optical band gaps of diamond.
J. H. L.-W. thanks the Engineering and Physical Sciences Research Council (UK) for a PhD studentship. B. M. thanks Robinson College, Cambridge, and the Cambridge Philosophical Society for a Henslow Research Fellowship. This work used the Cambridge High Performance Computing Service, for which access was funded by the EPSRC [EP/J017639/1], and the ARCHER UK National Supercomputing Service, for which access was obtained via the UKCP consortium and funded by the EPSRC [EP/K013564/1].
External DOI: https://doi.org/10.1103/PhysRevB.92.184301
This record's URL: https://www.repository.cam.ac.uk/handle/1810/252325
Attribution-NonCommercial 2.0 UK: England & Wales
Licence URL: http://creativecommons.org/licenses/by-nc/2.0/uk/
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