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Updated: Jul 1, 2026
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Characterization of Thermal Transport in One-dimensional Solid Materials
Published on: January 26, 2014
Modeling thermal transport in AlN/GaN superlattices and heterostructures with machine-learned force fields
1Institute of Solid State Physics, Graz University of Technology, Graz, Austria.
Summary
Investigating thermal transport in AlN/GaN superlattices reveals partially coherent acoustic transport even at room temperature. Anharmonicity plays a contrasting role at interfaces versus superlattices, impacting heat flow control.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Superlattices exhibit unique thermal transport regimes: coherent wave-like, ballistic incoherent, and diffusive.
- Coherent transport offers advanced control over heat flow via band-structure engineering and phononic filtering.
- Understanding thermal transport in heterostructures is crucial for advanced thermal management applications.
Purpose of the Study:
- To investigate thermal transport across AlN/GaN heterostructure interfaces and superlattices.
- To explore the influence of anharmonicity on thermal transport in these systems.
- To develop and validate models for predicting thermal boundary conductance and superlattice thermal conductivity.
Main Methods:
- Molecular dynamics simulations were employed to model thermal transport.
- The Atomistic Green's Function method was utilized in conjunction with a machine-learned force field.
- An inelastic extension of the diffuse mismatch model was developed to account for three-phonon processes.
Main Results:
- Inelastic phonon transmission significantly contributes to thermal boundary conductance at AlN/GaN interfaces.
- A minimum in superlattice thermal conductivity was observed around a 2 nm period.
- Signatures of partially coherent acoustic transport were detected at room temperature.
- Anharmonicity enhances interfacial conductance but suppresses superlattice thermal transport.
Conclusions:
- The study provides insights into the complex thermal transport mechanisms in AlN/GaN superlattices.
- Coherent acoustic transport phenomena persist at room temperature in these structures.
- The findings highlight the contrasting effects of anharmonicity in interfaces versus superlattices, crucial for designing thermal management materials.
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