title: Anisotropy of the thermal conductivity in GaAs/AlAs superlattices.
abstract: We combine the transient thermal grating and time-domain thermoreflectance techniques to characterize the anisotropic thermal conductivities of GaAs/AlAs superlattices from the same wafer. The transient grating technique is sensitive only to the in-plane thermal conductivity, while time-domain thermoreflectance is sensitive to the thermal conductivity in the cross-plane direction, making them a powerful combination to address the challenges associated with characterizing anisotropic heat conduction in thin films. We compare the experimental results from the GaAs/AlAs superlattices with first-principles calculations and previous measurements of Si/Ge SLs. The measured anisotropy is smaller than that of Si/Ge SLs, consistent with both the mass-mismatch picture of interface scattering and with the results of calculations from density-functional perturbation theory with interface mixing included.
authors: Department of Mechanical Engineering, ‡Department of Chemistry, and §Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors: Maria N
authors: MN
authors: Luckyanova
authors: Jeremy A
authors: JA
authors: Johnson
authors: A A
authors: AA
authors: Maznev
authors: Jivtesh
authors: J
authors: Garg
authors: Adam
authors: A
authors: Jandl
authors: Mayank T
authors: MT
authors: Bulsara
authors: Eugene A
authors: EA
authors: Fitzgerald
authors: Keith A
authors: KA
authors: Nelson
authors: Gang
authors: G
authors: Chen
mesh_terms: D016880:Anisotropy; D001152:Arsenicals / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry*; D006358:Hot Temperature; D008970:Molecular Weight; D049329:Nanostructures; D012825:Silicon / Q000737:chemistry; D013814:Thermal Conductivity
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium; D012825:Silicon