Experimental evidence of non-diffusive thermal transport in Si and GaAs

Jeremy A. Johnson, Alexei A. Maznev, Jeffrey K. Eliason, Austin Minnich, Kimberlee Collins, Gang Chen, John Cuffe, Timothy Kehoe, Clivia M. Sotomayor Torres, Keith A. Nelson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Scopus citations


The length-scales at which thermal transport crosses from the diffusive to ballistic regime are of much interest particularly in the design and improvement of nano-structured materials. In this work, we demonstrate that the departure from diffusive transport has been observed in Si and GaAs using an optical transient thermal grating technique where an arbitrary, experimentally set length scale can be imposed on a material. In a transient thermal grating experiment, crossed laser pulses interfere creating a well-defined periodic absorption and temperature profile. A probe beam is diffracted from this transient grating and length-scale dependent thermal transport properties can be determined from the signal decay. As the length scale is decreased to lengths shorter than the mean free paths of heat carrying phonons, quasi-ballistic heat transport effects become apparent allowing us to map out length scales and mean free paths relevant to non-diffusive thermal transport in Si and GaAs.

Original languageEnglish (US)
Title of host publicationNanoscale Heat Transport - From Fundamentals to Devices
Number of pages6
StatePublished - 2011
Event2011 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 25 2011Apr 29 2011

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2011 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA

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