Internal friction by electron hole pair recombination in tellurium

Arlt, G.; Hermann, W.

doi:10.1016/0038-1098(69)90696-6

Cited by 4 publications

(1 citation statement)

References 3 publications

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“…In such a case conditions comparable to those of excitonic states seem possible and the reduction of the transition temperature by the steady optical excitation could be explained by a kind of Mott transition. Such an assumption would be compatible with the internal friction results, since Southgate [12] for Ge and Si and Arlt and Hermann [24] for Te have proved a corresponding deformation potential damping by electronhole pair recombination. As a possible reason for those local potentials the random distribution of boron isotopes loB and llB may be considered, which, according to Berezin [25], leads to centres of intrinsic localization of Anderson type.…”

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confidence: 74%

States of Thermal Equilibrium in β‐Rhombohedral Boron and Their Alteration by Optical Excitation

Werheit¹,

Franz²

1984

Physica Status Solidi (b)

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It is shown that p-rhombohedra1 boron has different states of thermal equilibrium a t T 5 150 and 2 180 K. These states can be distinguished by their optical absorption spectra showing electronic transitions into a bound state at 0.4 eV at low temperatures, and transitions into an energy continuum a t higher temperatures. By steady state optical excitation the transition temperat,ure is lowered indicating a kind of Mott transition. This phase transition is assumed to be the reason for the discontinuity of numerous physical properties of P-rhombohedra1 boron in this range of temperature. E s wird nachgewiesen, daB P-rhomboedrisches Bor bei T 5 150 und 2 180 K verschiedene thermodynamische Gleichgewichtszustande besitzt. Diese werden anhand der optischen Absorptionsspektren unterschieden, die bei tiefen Temperaturen elektronische obergange in einen gebundenen Zustand bei 0,4 eV, bei hohen Temperaturen in ein Energiekontinuum zeigen. Durch stationare optische Erregung wird die Umwandlungstemperatur abgesenkt, was fur eine Art Mottttbergang spricht. Dieser Phasenubergang liefert eine Begrundung fur die Diskontinuitat diverser physikalischer Eigenschaften des P-rhomboedrischen Bors in diesem Temperaturbereich.

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supporting

confidence: 74%

States of Thermal Equilibrium in β‐Rhombohedral Boron and Their Alteration by Optical Excitation

Werheit¹,

Franz²

1984

Physica Status Solidi (b)

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Low temperature phase transition in β-rhombohedral boron

Werheit

Franz

1986

Journal of the Less Common Metals

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Elastic properties, damping capacity and shape memory alloys

1992

Smithells Metals Reference Book

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The elastic properties of a metal reflect the response of the interatomic forces between the atoms concerned to an applied stress. Since the bonding forces vary with crystallographic orientation the elastic properties of metal single crystals may be highly anisotropic. However, polycrystalline metals and alloys with a randomly oriented grain structure behave isotropically. Table 15.1 lists elastic constants for polycrystalline metals and alloys in an isotropic condition. Any preferred orientation or texture resulting from rolling, drawing or extrusion, for example, will result in departures from the listed values to a degree that depends upon the elastic anisotropy of the individual crystals (which may be deduced from the single crystal elastic constants of Tables 15.2 to 15.6 that follow) and the nature and extent of the preferred orientation.Since the elastic properties are determined by the aggregate response of the interatomic forces between all the atoms in the metal, the presence of small quantities of solute atoms in dilute alloys or their rearrangement by heat treatment will have relatively little effect on the absolute values of their elastic constants. Consequently, the elastic constants of all the plain carbon and low alloy steels will be approximately the same unless some preferred orientation is present. Similarly with Cu-, Al-and Ni-base dilute alloys, etc. In the case of concentrated alloys there may be larger variations in elastic moduli, especially where there is a drastic change in the relative proportions of different phases in a multiphase alloy. In the case of ideal solid solutions the elastic moduli vary linearly with atom fraction. The elastic moduli of non-ideal solid solutions may show positive or negative deviations from linearity. Ordering produces an increase in elastic moduli.Increase in temperature causes a gradual decrease in elastic moduli. The decrease is fairly linear over wider ranges of temperature but sharply increases in magnitude as the melting point is approached. Discontinuities are observed at structural transformations.Ferromagnetic materials having a high degree of domain mobility may exhibit considerably higher elastic moduli below the Curie point in the presence of a high magnetic field. The lower elastic moduli in the absence of a magnetic field are due to magnetostrictive dimensional changes caused by stress-induced domain movement. 15-1 15-2Elastic properties, damping capacity and shape memory alloys TaNe 15.

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Internal friction by electron hole pair recombination in tellurium

Cited by 4 publications

References 3 publications

States of Thermal Equilibrium in β‐Rhombohedral Boron and Their Alteration by Optical Excitation

States of Thermal Equilibrium in β‐Rhombohedral Boron and Their Alteration by Optical Excitation

Low temperature phase transition in β-rhombohedral boron

Elastic properties, damping capacity and shape memory alloys

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