Thermostat-induced spurious interfacial resistance in non-equilibrium molecular dynamics simulations of solid-liquid
Dhairyashil Ghatage1, Gaurav Tomar1, Ratnesh K Shukla1
1Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India.
The Journal of Chemical Physics
|November 3, 2020
Summary
Thermostats in non-equilibrium molecular dynamics (NEMD) simulations can create artificial temperature jumps at solid-liquid interfaces, affecting thermal transport. Optimizing thermostat parameters is crucial to balance temperature control with accurate interfacial thermal resistance measurements.
Area of Science:
- Computational Physics
- Materials Science
- Thermodynamics
Background:
- Non-equilibrium molecular dynamics (NEMD) simulations utilize thermostats for temperature control.
- Thermostats can inadvertently alter system dynamics, impacting molecular transport.
- Interfacial thermal transport is critical in many physical systems.
Purpose of the Study:
- To analyze the influence of thermostats on thermal transport across solid-liquid interfaces in NEMD simulations.
- To identify conditions leading to spurious temperature jumps and anomalous interfacial thermal resistance.
- To determine optimal thermostat parameters for accurate simulations.
Main Methods:
- Canonical NEMD simulation setup.
- Analysis of thermal transport across a solid-liquid interface.
- Investigation of stochastic/frictional forcing-based thermostats.
- Development of a simplified atomic impinging model.
Main Results:
- Stochastic/frictional thermostats induce spurious temperature jumps at solid-liquid interfaces.
- Interfacial thermal resistance (Kapitza length) is inversely related to thermostat coupling strength.
- Thermostat-induced alterations in force autocorrelation functions cause anomalous resistance.
- An optimal parameter range exists for balancing temperature control and interfacial resistance.
Conclusions:
- Judicious selection of thermostat control parameters is essential to avoid misleading MD-deduced temperature jumps.
- The findings are applicable to both solid-liquid interfaces and single-phase solid systems.
- A computationally inexpensive model is proposed for identifying significant thermostat-induced thermal resistance.
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