Ab initio electron-lattice downfolding: potential energy landscapes, anharmonicity, and molecular dynamics in charge density wave materials

Fuente: arXiv
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Auteurs principaux: Schobert, Arne, Berges, Jan, van Loon, Erik G. C. P., Sentef, Michael A., Brener, Sergey, Rossi, Mariana, Wehling, Tim O.
Format: Preprint
Publié: 2023
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author Schobert, Arne
Berges, Jan
van Loon, Erik G. C. P.
Sentef, Michael A.
Brener, Sergey
Rossi, Mariana
Wehling, Tim O.
author_facet Schobert, Arne
Berges, Jan
van Loon, Erik G. C. P.
Sentef, Michael A.
Brener, Sergey
Rossi, Mariana
Wehling, Tim O.
contents The interplay of electronic and nuclear degrees of freedom presents an outstanding problem in condensed matter physics and chemistry. Computational challenges arise especially for large systems, long time scales, in nonequilibrium, or in systems with strong correlations. In this work, we show how downfolding approaches facilitate complexity reduction on the electronic side and thereby boost the simulation of electronic properties and nuclear motion - in particular molecular dynamics (MD) simulations. Three different downfolding strategies based on constraining, unscreening, and combinations thereof are benchmarked against full density functional calculations for selected charge density wave (CDW) systems, namely 1H-TaS$_2$, 1T-TiSe$_2$, 1H-NbS$_2$, and a one-dimensional carbon chain. We find that the downfolded models can reproduce potential energy surfaces on supercells accurately and facilitate computational speedup in MD simulations by about five orders of magnitude in comparison to purely ab initio calculations. For monolayer 1H-TaS$_2$ we report classical replica exchange and quantum path integral MD simulations, revealing the impact of thermal and quantum fluctuations on the CDW transition.
format Preprint
id arxiv_https___arxiv_org_abs_2303_07261
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Ab initio electron-lattice downfolding: potential energy landscapes, anharmonicity, and molecular dynamics in charge density wave materials
Schobert, Arne
Berges, Jan
van Loon, Erik G. C. P.
Sentef, Michael A.
Brener, Sergey
Rossi, Mariana
Wehling, Tim O.
Strongly Correlated Electrons
Statistical Mechanics
Chemical Physics
Computational Physics
Quantum Physics
The interplay of electronic and nuclear degrees of freedom presents an outstanding problem in condensed matter physics and chemistry. Computational challenges arise especially for large systems, long time scales, in nonequilibrium, or in systems with strong correlations. In this work, we show how downfolding approaches facilitate complexity reduction on the electronic side and thereby boost the simulation of electronic properties and nuclear motion - in particular molecular dynamics (MD) simulations. Three different downfolding strategies based on constraining, unscreening, and combinations thereof are benchmarked against full density functional calculations for selected charge density wave (CDW) systems, namely 1H-TaS$_2$, 1T-TiSe$_2$, 1H-NbS$_2$, and a one-dimensional carbon chain. We find that the downfolded models can reproduce potential energy surfaces on supercells accurately and facilitate computational speedup in MD simulations by about five orders of magnitude in comparison to purely ab initio calculations. For monolayer 1H-TaS$_2$ we report classical replica exchange and quantum path integral MD simulations, revealing the impact of thermal and quantum fluctuations on the CDW transition.
title Ab initio electron-lattice downfolding: potential energy landscapes, anharmonicity, and molecular dynamics in charge density wave materials
topic Strongly Correlated Electrons
Statistical Mechanics
Chemical Physics
Computational Physics
Quantum Physics
url https://arxiv.org/abs/2303.07261