Title: Efficient perturbation-tracking method for directly probing the spectral phonon properties from molecular dynamics simulations

Abstract

Existing methods for directly extracting the spectral phonon properties from molecular dynamics (MD) simulations, like the normal mode analysis (NMA) and spectral energy density analysis, all require a very long simulation time to produce reliable results with good convergence. So far, these methods are mainly applied in studies using small systems and with empirical potentials, as the heavy computational load has greatly hindered their further applications. Here we propose a perturbation-tracking (PT) method for directly probing the mode-wise phonon anharmonic frequencies and lifetimes. We show that results obtained from our method are in excellent agreement with those from the conventional NMA approach, using Si as the model material system. Comparing with the NMA approach, the PT method offers a greater accuracy and significant improvement of efficiency. It takes an average of two orders of magnitude and up to three orders of magnitude less simulation time to obtain the same lifetime result of a phonon mode with intermediate to high accuracy. Meanwhile, our method preserves all the dynamics of probed phonon mode from a particular state, which means it is capable of studying the transient thermal transport processes in a nonequilibrium system. Besides the exceptional efficiency, our method also comes withmore » freedom to choose to probe only those modes of interest. This makes it ideal for use with large systems and in computationally demanding applications, such as ab initio MD simulations. Moreover, the PT method we propose here is very straightforward and easy to implement.« less

Authors:

Zheng, Zexi  ^[1];

• Search DOE PAGES for author "Zheng, Zexi"
• Search DOE PAGES for ORCID "0000-0002-3217-246X"

Li, Yang  ^[1];

• Search DOE PAGES for author "Li, Yang"
• Search DOE PAGES for ORCID "0000-0003-1171-0852"

Chen, Xiang ^[2]; Chen, Youping ^[1]

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+ Show Author Affiliations

1. Univ. of Florida, Gainesville, FL (United States)
2. Louisiana Tech Univ., Ruston, LA (United States)

Publication Date:

Thu Nov 19 00:00:00 EST 2020

Research Org.:

Univ. of Florida, Gainesville, FL (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1850947

Grant/Contract Number:  

SC0006539

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review. E

Additional Journal Information:

Journal Volume: 102; Journal Issue: 5; Journal ID: ISSN 2470-0045

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

74 ATOMIC AND MOLECULAR PHYSICS; Physics; Lattice thermal conductivity; Lifetimes & widths; Phonons; Molecular dynamics