title: Precise control of thermal conductivity at the nanoscale through individual phonon-scattering barriers.
abstract: The ability to precisely control the thermal conductivity (kappa) of a material is fundamental in the development of on-chip heat management or energy conversion applications. Nanostructuring permits a marked reduction of kappa of single-crystalline materials, as recently demonstrated for silicon nanowires. However, silicon-based nanostructured materials with extremely low kappa are not limited to nanowires. By engineering a set of individual phonon-scattering nanodot barriers we have accurately tailored the thermal conductivity of a single-crystalline SiGe material in spatially defined regions as short as approximately 15 nm. Single-barrier thermal resistances between 2 and 4 x 10(-9) m(2) K W(-1) were attained, resulting in a room-temperature kappa down to about 0.9 W m(-1) K(-1), in multilayered structures with as little as five barriers. Such low thermal conductivity is compatible with a totally diffuse mismatch model for the barriers, and it is well below the amorphous limit. The results are in agreement with atomistic Green's function simulations.
authors.affiliation: CPMOH, Université Bordeaux-CNRS, 351 cours de la Libération, 33405 Talence, France.
authors.forename: G
authors.initials: G
authors.lastname: Pernot
authors.forename: M
authors.initials: M
authors.lastname: Stoffel
authors.forename: I
authors.initials: I
authors.lastname: Savic
authors.forename: F
authors.initials: F
authors.lastname: Pezzoli
authors.forename: P
authors.initials: P
authors.lastname: Chen
authors.forename: G
authors.initials: G
authors.lastname: Savelli
authors.forename: A
authors.initials: A
authors.lastname: Jacquot
authors.forename: J
authors.initials: J
authors.lastname: Schumann
authors.forename: U
authors.initials: U
authors.lastname: Denker
authors.forename: I
authors.initials: I
authors.lastname: Mönch
authors.forename: Ch
authors.initials: Ch
authors.lastname: Deneke
authors.forename: O G
authors.initials: OG
authors.lastname: Schmidt
authors.forename: J M
authors.initials: JM
authors.lastname: Rampnoux
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Plissonnier
authors.forename: A
authors.initials: A
authors.lastname: Rastelli
authors.forename: S
authors.initials: S
authors.lastname: Dilhaire
authors.forename: N
authors.initials: N
authors.lastname: Mingo