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Heat generation and transport due to time-dependent forces
Bijay Kumar Agarwalla1, Jian-Sheng Wang, Baowen Li
1Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542, Republic of Singapore.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 21, 2011
Summary
This study analyzes heat transport in solids under time-dependent forces using nonequilibrium Green's function methods. It reveals heat current depends on atomic displacement and bath self-energy, offering insights into thermal properties.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Statistical Mechanics
Background:
- Understanding heat generation and transport in solids is crucial for designing advanced materials and devices.
- External time-dependent forces introduce complex dynamics to thermal properties.
- Nonequilibrium phenomena are key to many physical processes.
Purpose of the Study:
- To derive an exact analytical expression for heat current in solids under arbitrary time-dependent forces.
- To investigate the dependence of steady-state heat current on frequency and system size.
- To explore the role of atomic displacement, bath self-energy, and density of states in heat transport.
Main Methods:
- Utilizing the nonequilibrium Green's function (NEGF) approach for an exact analytical solution.
- Analyzing linear systems subjected to arbitrary time-dependent forces.
- Performing calculations for periodic driving forces in one- and two-dimensional systems.
Main Results:
- An exact analytical expression for heat current was derived, dependent on atomic displacement and heat bath self-energy.
- Steady-state current was analyzed for periodic driving forces, showing dependence on frequency and system size.
- For a 1D linear chain with a Rubin bath, heat current related to density of states and independent of bath temperature in ballistic transport.
Conclusions:
- The study provides a theoretical framework for understanding heat transport under external time-dependent forces.
- Heat current is significantly influenced by system-specific properties like density of states and external driving frequencies.
- Energy absorption by baths is limited to frequencies within the phonon band, highlighting frequency-dependent thermal dynamics.
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