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Full-Text Articles in Physics

Defect Structure Of Sb2−Xmnxte3 Single Crystals., Jaromír Horák, Petr LošŤÁK, Čestmír Drašar, Jeffrey Dyck, Zengzua Zhou, Cterid Uher Aug 2005

Defect Structure Of Sb2−Xmnxte3 Single Crystals., Jaromír Horák, Petr LošŤÁK, Čestmír Drašar, Jeffrey Dyck, Zengzua Zhou, Cterid Uher

Jeffrey Dyck

Incorporation of the transition metal elements in the tetradymite structure of Sb2Te3 has a strong influence on electronic properties. Recent studies have indicated that Mn substitutes on the Sb sublattice increases the carrier concentration of holes. However, the doping efficiency of Mn appears rather low in comparison to what it should be based on the measurements of magnetization, structural analysis, and transport properties. In this paper we address this issue by making detailed studies of the Hall effect and electrical resistivity and we explain the results with the aid of a model that takes into account interactions of the Mn …


Genetic Programming For Multitimescale Modeling, Kumara Sastry, Duane D. Johnson, David E. Goldberg, Pascal Bellon Aug 2005

Genetic Programming For Multitimescale Modeling, Kumara Sastry, Duane D. Johnson, David E. Goldberg, Pascal Bellon

Duane D. Johnson

A bottleneck for multitimescale thermally activated dynamics is the computation of the potential energy surface. We explore the use of genetic programming (GP) to symbolically regress a mapping of the saddle-point barriers from only a few calculated points via molecular dynamics, thereby avoiding explicit calculation of all barriers. The GP-regressed barrier function enables use of kinetic Monte Carlo to simulate real-time kinetics (seconds to hours) based upon realistic atomic interactions. To illustrate the concept, we apply a GP regression to vacancy-assisted migration on a surface of a concentrated binary alloy (from both quantum and empirical potentials) and predict the diffusion …


Transport Coefficients Of Titanium-Doped Sb2te3 Single Crystals., Č. Drašar, M. Steinhart, P. Lošťák, H.-K. Shin, Jeffrey Dyck, C. Uher Mar 2005

Transport Coefficients Of Titanium-Doped Sb2te3 Single Crystals., Č. Drašar, M. Steinhart, P. Lošťák, H.-K. Shin, Jeffrey Dyck, C. Uher

Jeffrey Dyck

Titanium-doped single crystals (cTi=0–2×1020atomscm−3) were prepared from the elements Sb, Ti, and Te of 5N purity by a modified Bridgman method. The obtained crystals were characterized by measurements of the temperature dependence of the electrical resistivity, Hall coefficient, Seebeck coefficient and thermal conductivity in the temperature range of 3–300K. It was observed that with an increasing Ti content in the samples the electrical resistivity, the Hall coefficient and the Seebeck coefficient increase. This means that the incorporation of Ti atoms into the Sb2Te3 crystal structure results in a decrease in the concentration of holes in the doped crystals. For the …


Thermodynamics, Structure, And Dynamics Of Water Confined Between Hydrophobic Plates, Francis Starr, P. Kumar, S. Buldyrev, N. Giovambattista, H. Stanley Jan 2005

Thermodynamics, Structure, And Dynamics Of Water Confined Between Hydrophobic Plates, Francis Starr, P. Kumar, S. Buldyrev, N. Giovambattista, H. Stanley

Francis Starr

No abstract provided.


Clusters Of Mobile Molecules In Supercooled Water, Nicolas Giovambattista, Sergey Buldyrev, H. Stanley, Francis Starr Jan 2005

Clusters Of Mobile Molecules In Supercooled Water, Nicolas Giovambattista, Sergey Buldyrev, H. Stanley, Francis Starr

Francis Starr

No abstract provided.


Vibrational Dependence Of The H2–H2 C6 Coefficients, Robert Hinde Jan 2005

Vibrational Dependence Of The H2–H2 C6 Coefficients, Robert Hinde

Robert Hinde

We use the sum-over-states formalism to compute the imaginary-frequency dipole polarizabilities for H2, as a function of the H–H bond length, at the full configuration interaction level of theory using atom-centered d-aug-cc-pVQZ basis sets. From these polarizabilities, we obtain isotropic and anisotropic C6 dispersion coefficients for a pair of H2 molecules as functions of the two molecules’ bond lengths.


Spatially Heterogeneous Dynamics And The Adam-Gibbs Relation In The Dzugutov Liquid, Yeshitela Gebremichael, M Vogel, M Bergroth, Francis W. Starr, Sharon C. Glotzer Dec 2004

Spatially Heterogeneous Dynamics And The Adam-Gibbs Relation In The Dzugutov Liquid, Yeshitela Gebremichael, M Vogel, M Bergroth, Francis W. Starr, Sharon C. Glotzer

Francis Starr

No abstract provided.