相关论文: Role of force-constant difference in phonon scatte…
We present a comprehensive experimental and theoretical study of phonon scattering by nanoprecipitates in potassium-doped PbTe, PbSe and PbS. We highlight the role of the precipitate size distribution measured by microscopy, whose tuning…
We calculate the thermal conductivity of PbTe and PbS with seven different types of nanoprecipitates using an ab-initio-based Boltzmann transport approach. We find that precipitates with realistic size distributions can reduce the thermal…
Solid-state precipitation can be used to tailor materials properties, ranging from ferromagnets and catalysts to mechanical strengthening and energy storage. Thermoelectric properties can be modified by precipitation to enhance phonon…
Understanding phonon scattering by topological defects in graphene is of particular interest for thermal management in graphene-based devices. We present a study that quantifies the roles of the different mechanisms governing defect phonon…
We report first principles calculations of the phonon dispersions of PbTe both for its observed structure and under compression. At the experimental lattice parameter we find a near instability of the optic branch at the zone center, in…
Prior experimental studies showed that nanowires are promising structures for improving the thermoelectric performance of practical thermoelectric materials due to the strongly induced phonon-boundary scattering. However, few studies…
This study presents a comprehensive computational investigation of magnetite nanoparticles, systematically evaluating a range of force fields against experimental results. We analyze the influence of particle size, temperature, and…
PbTe, one of the most promising thermoelectric materials, has recently demonstrated thermoelectric figure of merit ($ZT$) of above 2.0 when alloyed with group II elements. The improvements are due mainly to significant reduction of lattice…
We study the temperature dependence of thermoelectric transport properties of four FeSb2 nanocomposite samples with different grain sizes. The comparison of the single crystals and nanocomposites of varying grain size indicates the presence…
Heat transport in nanoscale systems is both hard to measure microscopically, and hard to interpret. Ballistic and diffusive heat flow coexist, adding confusion. This paper looks at a very simple case: a nanoscale crystal repeated…
Materials with very low thermal conductivity are of high interest for both thermoelectric and optical phase-change applications. Synthetic nanostructuring is most promising to suppress thermal conductivity by scattering phonons, but…
The phonon thermal contribution to the melting temperature of nano-particles is inspected. The discrete summation of phonon states and its corresponding integration form as an approximation for a nano-particle or for a bulk system have been…
We investigate the harmonic and anharmonic contributions to the phonon spectrum of lead telluride, and perform a complete characterization of how the anharmonic effects dominate the phonons in PbTe as temperature increases. This effect is…
The effect of interface scattering on the performance of disordered, nanocomposite thermoelectric materials is studied theoretically using effective medium theory and direct numerics. The interfacial electronic and phonon scattering…
Understanding the microscopic processes affecting the bulk thermal conductivity is crucial to develop more efficient thermoelectric materials. PbTe is currently one of the leading thermoelectric materials, largely thanks to its low thermal…
Dislocations can greatly enhance the figure of merit of thermoelectric materials by prominently reducing thermal conductivity. However, the evolution of phonon modes with different energies when they propagate through a single dislocation…
First-principles phonon calculations have been widely performed for studying vibrational properties of condensed matter, where the dynamical matrix is commonly constructed via supercell force-constant calculations or the linear response…
Inelastic neutron scattering measurements are utilized to explore relative changes in the generalized phonon density of states of nanocrystalline Si1xGex thermoelectric materials prepared via ball milling and hot-pressing techniques.…
The standard definition of particle number fluctuations based on point-like particles neglects the excluded volume effect. This leads to a large and systematic finite-size scaling and an unphysical surface term in the isothermal…
The major obstacle in the design of materials with low lattice thermal conductivity is the difficulty in efficiently scattering phonons across the entire frequency spectrum. Using first principles calculations, we show that driving PbTe…