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A Simple Analysis of the Einstein Relation in Ultrathin Films of Nonparabolic Semiconductors in the Presence of an Arbitrarily Oriented Magnetic Field
Author(s) -
Ghatak K. P.,
Bhattacharya D.,
Basu D.,
Nag B.
Publication year - 1995
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221910115
Subject(s) - einstein relation , thermal diffusivity , condensed matter physics , degenerate energy levels , semiconductor , magnetic field , dispersion relation , materials science , electron , electron mobility , band gap , alloy , degenerate semiconductor , lattice constant , lattice (music) , dispersion (optics) , physics , quantum mechanics , optoelectronics , metric (unit) , operations management , acoustics , economics , composite material , diffraction
Abstract An attempt is made to study the Einstein relation of the diffusivity—mobility ratio of carriers in ultrathin films of nonparabolic semiconductors in the presence of an arbitrarily oriented magnetic field. This is done on the basis of a new electron dispersion law. It is found, taking Hg 1− x Cd x Te and In 1− x Ga x As y P 1− y lattice‐matched to InP as examples, that the diffusivity‐mobility ratio increases with increasing surface electron concentration and decreasing alloy composition and film thickness in various oscillatory manners. The magnetic field enhances the numerical value of the diffusivity‐mobility ratio and an experimental method is suggested to determine it in degenerate materials with arbitrary dispersion laws. In addition, the well‐known corresponding results for relatively wide‐gap materials in the absence of a magnetic field are obtained as special cases of our generalized analysis.