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Selected Works

Condensed Matter Physics

Thermoconductivity

Articles 1 - 3 of 3

Full-Text Articles in Physics

Heat Transport In Sb2àXvxte3 Single Crystals, Jeffrey Dyck, W. Chen, C. Uher, Č. DrašAr, P. LošŤÁK Sep 2002

Heat Transport In Sb2àXvxte3 Single Crystals, Jeffrey Dyck, W. Chen, C. Uher, Č. DrašAr, P. LošŤÁK

Jeffrey Dyck

Antimony telluride doped with small concentrations of vanadium was recently identified as a diluted magnetic semiconductor. We present a study of the heat transport in single crystals of [formula] with [formula] 0.01, 0.02, and 0.03. Thermopower and thermal conductivity were measured from 1.5 K to 300 K. The thermopower is positive for all samples investigated and has a modest dependence on vanadium content. At low temperatures, the lattice thermal conductivity has an approximate [formula] dependence and the data up to 100 K can be fitted well assuming that phonons scatter on boundaries, point defects, charge carriers ...


Transport Properties Of Polycrystalline Type-I Sn Clathrates, G. S. Nolas, J. L. Cohn, Jeffrey Dyck, C. Uher, J. Lang Apr 2002

Transport Properties Of Polycrystalline Type-I Sn Clathrates, G. S. Nolas, J. L. Cohn, Jeffrey Dyck, C. Uher, J. Lang

Jeffrey Dyck

Thermal conductivity, resistivity, Seebeck coefficient, and Hall measurements on polycrystalline Sn-clathrate compounds with the type-I hydrate crystal structure are reported. Interstitial alkali-metal atoms in these compounds reside inside polyhedral cavities formed by the tetrahedrally bonded Sn network atoms. Localized disorder associated with “rattling” motion of these interstitial atoms contributes to the low thermal conductivity of these semiconducting compounds. The Hall coefficient and resistivity for some compounds exhibit nonmonotonic temperature dependences consistent with a crossover with decreasing temperature from conduction-band to impurity-band conduction. The carrier mobility is found to be low even in the absence of interstitial atoms within the Sn ...


Influence Of Electron-Phonon Interaction On The Lattice Thermal Conductivity Of Co1àXnixsb3, J. Yang, D. T. Morelli, G. P. Meisner, W. Chen, Jeffrey Dyck, C. Uher Feb 2002

Influence Of Electron-Phonon Interaction On The Lattice Thermal Conductivity Of Co1àXnixsb3, J. Yang, D. T. Morelli, G. P. Meisner, W. Chen, Jeffrey Dyck, C. Uher

Jeffrey Dyck

We have investigated the effect of electron-phonon scattering in a series of n-type nickel-doped [formula] skutterudite materials. Samples were polycrystalline of the form [formula] with [formula] 0.001, 0.003, 0.005, 0.0075, and 0.01. The lattice thermal conductivity decreases dramatically with increasing Ni doping for [formula] For higher Ni concentration the reduction of the lattice thermal conductivity saturates. Our theoretical analysis indicates that this reduction of the lattice thermal conductivity cannot be explained solely by point-defect scattering of the phonons. Rather, we can fit the lattice thermal conductivity of Ni-doped [formula] by introducing an electron-phonon scattering mechanism ...