A simple approximation to the electron-phonon interaction in population dynamics
File(s)DLVKE-submitted.pdf (1.94 MB)
Accepted version
Author(s)
Bustamante, Carlos
Todorov, Tchavdar
Sanchez, Cristian
Horsfield, Andrew
Scherlis, Damian
Type
Journal Article
Abstract
The modeling of coupled electron–ion dynamics including a quantum description of the nuclear degrees of freedom has remained a costly and technically difficult practice. The kinetic model for electron–phonon interaction provides an efficient approach to this problem, for systems evolving with low amplitude fluctuations, in a quasi-stationary state. In this work, we propose an extension of the kinetic model to include the effect of coherences, which are absent in the original approach. The new scheme, referred to as Liouville–von Neumann + Kinetic Equation (or LvN + KE), is implemented here in the context of a tight-binding Hamiltonian and employed to model the broadening, caused by the nuclear vibrations, of the electronic absorption bands of an atomic wire. The results, which show close agreement with the predictions given by Fermi’s golden rule (FGR), serve as a validation of the methodology. Thereafter, the method is applied to the electron–phonon interaction in transport simulations, adopting to this end the driven Liouville–von Neumann equation to model open quantum boundaries. In this case, the LvN + KE model qualitatively captures the Joule heating effect and Ohm’s law. It, however, exhibits numerical discrepancies with respect to the results based on FGR, attributable to the fact that the quasi-stationary state is defined taking into consideration the eigenstates of the closed system rather than those of the open boundary system. The simplicity and numerical efficiency of this approach and its ability to capture the essential physics of the electron–phonon coupling make it an attractive route to first-principles electron–ion dynamics.
Date Issued
2020-12-21
Date Acceptance
2020-11-30
Citation
Journal of Chemical Physics, 2020, 153 (23)
ISSN
0021-9606
Publisher
American Institute of Physics
Journal / Book Title
Journal of Chemical Physics
Volume
153
Issue
23
Copyright Statement
© 2020 Author(s). Published under license by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Chemical Physics and may be found at https://aip.scitation.org/doi/10.1063/5.0031766
Sponsor
Commission of the European Communities
Grant Number
823897
Subjects
Science & Technology
Physical Sciences
Chemistry, Physical
Physics, Atomic, Molecular & Chemical
Chemistry
Physics
MOLECULAR-DYNAMICS
CONDUCTORS
EHRENFEST
Chemical Physics
02 Physical Sciences
03 Chemical Sciences
09 Engineering
Publication Status
Published
Article Number
ARTN 234108
Date Publish Online
2020-12-17