Showing papers by "Somnath Ghosh published in 1981"

Application of linear response theory in a coupled cluster framework for the calculation of ionization potentials

Abstract: A previous application [1] of linear response theory to the direct calculation of transition energies is extended to the direct calculation of ionization potentials.

Effect of size quantization on the Einstein relation in ultrathin films of non-parabolic semiconductors

Abstract: An attempt is made to investigate the effect of size quantization on the diffusivity-mobility ratio of the carriers in ultrathin films of semiconductors having Kane-type nonparabolic energy bands. It is shown, takingn-type InSb as an example, that the ratio oscillates both with increasing film thickness and with increasing carrier concentration under degenerate conditions and remains unaffected otherwise. The corresponding results for parabolic semiconductors are also obtained from the expressions derived.

Oscillatory effective mass in degenerate narrow-gap semiconductors in a quantizing magnetic field

Abstract: An attempt is made to study the effect of a quantizing magnetic field on the effective electron mass in degeneraten-type narrow-gap semiconductors at low temperatures. It is found, takingn-Hg1−xCdxTe as an example, that the effective electron mass shows an oscillatory magnetic-field dependence as is expected because of the dependence of the effective mass in degenerate non-parabolic bands on Fermi energy which oscillates with changing magnetic field. The amplitude of oscillations is, however, found to be significantly influenced by the alloy composition whereas the period is found to be independent of the band non-parabolicity, i.e. of the compositional parameter in ternary semiconductors.

Influence of alloy composition on the dependence of the diffusivity-mobility ratio in ternary semiconductors on a quantizing magnetic field

Abstract: An expression is derived for the diffusivity-mobility ratio in degenerate narrow-gap ternary semiconductors in the presence of a quantizing magnetic field. With the help of this expression, the diffusivity-mobility ratio is shown, taking n-Hg1−xCdxTe as an example, to have an oscillatory dependence on a quantizing magnetic field. The influence of alloy composition on such dependence is also investigated.

Effect of Magnetic Quantization on the Diffusivity—Mobility Ratio in n-Cd3As2

Abstract: An attempt is made to study the dependence of the diffusivity-mobility ratio on a quantizing magnetic field in degenerate n-Cd3As2 in the extreme quantum limit according to the Bodnar model which has recently been shown in the literature to be the most valid model for Cd3As2. The results obtained are then compared to those derived on the basis of the Kane model since many authors have continued to use the Kane model for Cd3As2. Es wird der Versuch unternommen, die Abhangigkeit des Diffusions—Beweglichkeitsverhaltnisses im quantisierenden Magnetfeld in entartetem n-Cd3As2 im extremen Quantengrenzfall entsprechend dem Modell von Bodnar zu bestimmen, von dem kurzlich in der Literatur gezeigt wurde, das es das verlaslichste Modell fur Cd3As2 darstellt. Die erhaltenen Ergebnisse werden dann mit denen verglichen, die auf der Grundlage des Modells von Kane abgeleitet wurden, da viele Autoren nach wie vor das Kanesche Modell fur Cd3As2 benutzen.

Effect of carrier degeneracy on the diffusivity-mobility ratio in n-Cd3As2

Abstract: An attempt is made to study the dependence of the diffusivity-mobility ratio on carrier concentration in degenerate n-Cd3As2 according to the Bodnar model which has recently been shown in the literature from studies on magnetic quantization to be the most valid model for Cd3As2. The results obtained are then compared with those derived on the basis of the Kane model to indicate the amount of error that would be involved with the use of the same model since many authors have continued to use it for Cd3As2.