Friday, September 18 • 2:30 PM – IMS, Rm. 20
Can Other Materials Besides Diamond have Ultrahigh Thermal Conductivity?
David A. Broido
Professor of Physics Boston College, Chestnut Hill, Massachusetts
Abstract: Diamond and its carbon cousins, graphite and graphene, have long been known to have by far the highest thermal conductivities (κ) of any materials, achieving room temperature values of over 2000 Wm-1 K-1 . Other ‘high κ’ materials such as copper (κ=400 Wm-1 K-1 ) have significantly lower values. In spite of welldefined criteria to guide the search for new high κ materials, little progress has been made over the years. In this talk, I will describe a novel paradigm for achieving high κ that we have recently proposed. This paradigm introduces new criteria, which stem from fundamental vibrational properties that occur in compounds where the constituent atoms have a large mass ratio. We have calculated the lattice thermal conductivities of candidate materials using a first principles theoretical approach that combines an exact solution of the Boltzmann transport equation for phonons with accurate determination of the harmonic and anharmonic interatomic forces from density functional theory. We have demonstrated excellent agreement with the measured thermal conductivities of a wide range of materials, validating the predictive capability of this theory and contributing insight into the nature of thermal transport in materials. Guided by the new paradigm, we have identified one material, cubic boron arsenide, that should have an exceptionally high room temperature κ comparable to the highest known bulk value achieved in diamond. This finding opens opportunities for controlling phonon thermal transport, which may facilitate the design of new high κ materials for thermal management applications.
Biographical Sketch: David Broido is currently a Professor of Physics at Boston College. He received his Ph.D. degree in Theoretical Physics from the University of California at San Diego in 1985. He was a National Research Council Postdoctoral Fellow at the U.S. Naval Research Laboratory before coming to Boston College in 1987. He is a Fellow of the American Physical Society. His research interests include theoretical studies of thermal and thermoelectric transport properties of materials using first principles approaches. https://www.bc.edu/schools/cas/physics/people/david_broido