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A Summary of the Theory and Design Team Efforts for the Sandia Metamaterials Science and Technology Grand Challenge LDRD

Basilio, Lorena I.; Brener, Igal B.; Burckel, David B.; Shaner, Eric A.; Wendt, J.R.; Luk, Ting S.; Ellis, A.R.; Bender, Daniel A.; Clem, Paul G.; Rasberry, Roger D.; Langston, William L.; Ihlefeld, Jon I.; Dirk, Shawn M.; Warne, Larry K.; Peters, D.W.; El-Kady, I.; Reinke, Charles M.; Loui, Hung L.; Williams, Jeffery T.; Sinclair, Michael B.; McCormick, Frederick B.

Abstract not provided.

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TYPE Presentation YEAR 2012
OSTI

Thermal conductivity manipulation in lithographically patterned single crystal silicon phononic crystal structures

IEEE International Ultrasonics Symposium, IUS

Kim, Bongsang; Nguyen, Janet; Reinke, Charles M.; Shaner, Eric A.; Harris, Charles T.; El-Kady, I.; Olsson, Roy H.

The thermal conductivity of single crystal silicon was engineered using lithographically formed phononic crystals. Specifically, sub-micron periodic through-holes were patterned in 500nm-thick silicon membranes to construct phononic crystals, and through phonon scattering enhancement, heat transfer was significantly reduced. The thermal conductivity of silicon phononic crystals was measured as low as 32.6W/mK, which is a ∼75% reduction compared to bulk silicon thermal conductivity [1]. This corresponds to a 37% reduction even after taking into account the contributions of the thin-film and volume reduction effects, while the electrical conductivity was reduced only by as much as the volume reduction effect. The demonstrated method uses conventional lithography-based technologies that are directly applicable to diverse micro/nano-scale devices, leading toward huge performance improvements where heat management is important. © 2011 IEEE.

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TYPE Conference YEAR 2011
ScopusOSTI

Manipulation of thermal phonons: A phononic crystal route to High-ZT thermoelectrics

Proceedings of SPIE - The International Society for Optical Engineering

El-Kady, I.; Su, Mehmet F.; Reinke, Charles M.; Hopkins, Patrick E.; Goettler, Drew; Leseman, Zayd C.; Shaner, Eric A.; Olsson, Roy H.

Phononic crystals (PnCs) are acoustic devices composed of a periodic arrangement of scattering centers embedded in a homogeneous background matrix with a lattice spacing on the order of the acoustic wavelength. When properly designed, a superposition of Bragg and Mie resonant scattering in the crystal results in the opening of a frequency gap over which there can be no propagation of elastic waves in the crystal, regardless of direction. In a fashion reminiscent of photonic lattices, PnC patterning results in a controllable redistribution of the phononic density of states. This property makes PnCs a particularly attractive platform for manipulating phonon propagation. In this communication, we discuss the profound physical implications this has on the creation of novel thermal phenomena, including the alteration of the heat capacity and thermal conductivity of materials, resulting in high-ZT materials and highly-efficient thermoelectric cooling and energy harvesting. © 2011 SPIE.

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TYPE Conference YEAR 2011
ScopusOSTI
Results 51–75 of 131
Results 51–75 of 131