McGaughey reflects on 25 years of nanoscale heat transfer modeling

For more than two decades, Alan McGaughey has been at the forefront of understanding how heat moves at the smallest scales. In a new perspective paper published in the Journal of Materials Science: Materials Theory, the Carnegie Mellon Mechanical Engineering professor looks back on 25 years of advances in nanoscale thermal transport modeling and offers a roadmap for the field’s future.

McGaughey’s work focuses on how the vibration of atoms, known as phonons, carry heat through materials and how their behavior can be predicted using computer simulations. Over the last twenty years,  advances in molecular dynamics and lattice dynamics techniques have transformed the field, enabling researchers to calculate thermal conductivity in materials ranging from crystalline solids to disordered systems. 

“Computational modeling is central to understanding thermal transport,” McGaughey said. “But getting reliable results requires more than running simulations and calculations. It depends on understanding the underlying physics and making careful methodological choices.”

Drawing from his research group’s experiences, McGaughey outlines best practices for widely used techniques for calculating thermal conductivity. He emphasizes that seemingly small decisions can significantly affect results.

The paper also underlines the importance of carefully comparing simulations with experimental data. 

“Achieving agreement between theory and experiment is meaningful,” he said. “But the comparison is often more complex than it appears. Differences between models and real-world measurements can stem from unknown sample conditions or limitations in computational approximations.”

At CMU, collaboration with experimental researchers like Jon Malen, professor of mechanical engineering,  has helped him to explain heat transfer in nanomaterials and hybrid systems.  This longstanding collaboration not only validates his computational models, but inspires new research directions. The pair has been working to design polymers  with ultra-high thermal conductivity to understand heat flow in emerging technologies. 

“Alan’s work gives us a window into thermal behavior that we simply can’t access through experiments alone,” Malen said. “By combining modeling with measurement, we’re able to build a more complete picture of how heat moves through complex materials.”

What once was a niche area has become a vibrant, global research community with many opportunities ahead.

Alan McGaughey, Professor, Mechanical Engineering

Looking ahead, McGaughey notes that machine-learned interatomic potentials are enabling simulations with near quantum-level accuracy, and new theoretical frameworks and open source tools are making advanced simulations more accessible. 

“These advances are opening the door to study more complex materials, and answer questions about how heat moves through matter.”

For McGaughey, the field’s rapid growth has been energizing.

“What once was a niche area has become a vibrant, global research community with many opportunities ahead.”