Garg’s Research Advances

Jivtesh GargDr. Jivtesh Garg, AME Assistant Professor, and fellow research members recently developed a model that explains how heat flows between objects separated by gaps of less than a nanometer. The team has developed an atomistic framework that successfully predicts the magnitude of heat transfer across all gaps ranging from finite sizes all the way to perfect contact. The work overcomes the shortcomings of previous continuum based models which predict a diverging behavior at short length scales.

Through this model the team demonstrated that at gaps of few atomic layers, lattice vibrations (phonons) can tunnel through (normally associated with conduction heat transfer) in addition to heat transfer through evanescent electromagnetic modes (near-field radiation) blurring the separation between conduction and radiation at short length scales. By using microscopic Maxwell’s equations energy transfer was directly expressed in terms of short-range forces and long-range Coulomb forces between atoms on either side of a gap avoiding the need for use of any bulk macroscopic properties such as the dielectric constant. Such a purely atomistic framework of describing heat transfer can also benefit from ab-initio calculations that provide short-range interactions through solution of the underlying quantum-mechanical problem.

The work has implications for practical applications where heat transfer at small gaps is becoming increasingly relevant such as heat-assisted magnetic recording and nano-structured aerogel materials. By providing an accurate atomistic description the work also paves way for development of non-local dielectric constant which can be integrated into continuum models allowing an easier prediction of thermal transport at these small gaps.

The research team is made up of Vazrik Chiloyan, Massachusetts Institute of Technology; Keivan Esfarjani, Rutgers University; Gang Chen, Massachusetts Institute of Technology; and Jivtesh Garg. To view the paper regarding the team’s work, please click here. Additionally, the team’s work was recently featured in MIT News.

Leave a Reply

Your email address will not be published. Required fields are marked *