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Showing 1 to 11 of 11 for “"Phonon drag"”.
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First-principles study of phonon drag effect in SiGe alloys
… refrigerators. First discovered in the 1950s, phonon drag effect describes the phenomenon that the Seebeck coefficients of semiconductors are often enormously augmented at low temperatures.
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Ab initio simulation and optimization of phonon drag effect for lower-temperature thermoelectric energy
… first-principles simulation tools to study the phonon drag effect - a coupling phenomenon between electrons and non-equilibrium phonons - that leads to a large Seebeck coefficient at low temperatures. Phonon drag effect is simulated successfully from first-principles for the first time and …
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Experimental Quantification of the Phonon Drag Deformation Mechanism in Metals at Extreme Strain Rates
… from ballistic transport of dislocations from phonon interactions in the crystal lattice. These effects are quantified systematically and it is shown that the anomalous thermal strengthening seen is, thermodynamically and kinetically, the expected form of plasticity under these impact …
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The pressure dependence of the thermoelectric power of sodium between 5°K and 14°K
… power of sodium between 5°K and l4°K where phonon drag is believed to play a prominent role. A Superconducting Quantum Interference Device (""SQUID"") was used to measure the tiny voltages involved. At 1 and 2 kilobars no effect was observable, but at 3 kilobars the thermoelectric power was …
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Effect of phonon transport on the Seebeck coefficient and thermal conductivity of silicon nanowire arrays
… to the increased scattering of heat conducting phonons from the surface disorder introduced by etching. The reduction is below the incoherent limit for phonon scattering at the boundary, the so-called Casimir limit. A new model of partially coherent phonon transport shows that correlated …
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The plastic behavior of predeformed ice crystals
… viscosity results from a Snoek-type viscous drag arising from proton rearrangement in the stress field of the dislocations, as suggested by Weertman. Since the viscous drag constant at -100 C is about seven orders of magnitude greater than typical room temperature phonon drag constants, the …
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Electrical and thermal transport in 2- and 3-dimensional periodic holey silicon
… the reduction to be explained through quenched phonon drag resulting from phonon boundary scattering. The thermal conductivity of these samples remain relatively in agreement with the Casimir limit. The total increase of ZT is 4 times when compared against bulk silicon at 300 K. The second part …
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Thermoelectric Energy Conversion: First-principles Simulations, Energy Harvesting and Deep Cooling Systems
… without fitting parameters. Surprisingly, the phonon drag effect that is supposed to be only significant at low temperatures still contributes to 10-20% of zT at 1100 K in SiGe alloys. The favorable comparison between our calculations and reported experiments brings us closer to predicting the …
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Phonon Spectroscopy and Low-Dimensional Electron Systems
… propagation of pulses of nonequilibrium acoustic phonons and their interaction with semiconductor nanostructures are investigated. Such studies can give unique information about the properties of low-dimensional electron systems, but in order to interpret the experiments and to understand the …
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One-Dimensional Quantum Magnets in Cuprates: Single Crystal Growth and Magnetic Heat Transport Studies
… heat transport which in some cases exceed the phonon contributions by more than one order of magnitude. Despite of intense ongoing experimental and theoretical investigations, the underlying mechanism of the magnetic heat transport remains unclear. The study of κ_mag aims a better understanding …
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Carrier momentum relaxation in highly doped polar semiconductors and semiconductor heterostructures
… of the carriers (plasmons) and the atoms (polar phonons) couple. These coupled collective excitations affect the electrical conductivity, here quantified through the carrier mobility. In scattering events, the carriers and the coupled collective modes transfer momentum between each other. Carrier …