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On the Einstein Relation in Ultrathin Films of IV–VI Compounds in the Presence of a Parallel Magnetic Field
Author(s) -
Ghatak K. P.,
Mitra B.,
Nag B.
Publication year - 1997
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 - 10.1002/1521-3951(199701)199:1<95::aid-pssb95>3.0.co;2-6
Subject(s) - einstein relation , magnetic field , condensed matter physics , degenerate energy levels , thermal diffusivity , electron , seebeck coefficient , materials science , einstein , electron mobility , dispersion (optics) , field (mathematics) , dispersion relation , degenerate semiconductor , thermoelectric effect , chemistry , physics , thermodynamics , quantum mechanics , mathematics , metric (unit) , operations management , pure mathematics , economics
We have studied the Einstein relation for the diffusivity—mobility ratio of carriers in ultrathin films of IV–VI compounds in the presence of a parallel magnetic field at low temperatures on the basis of a new 2D electron dispersion law. It is found, taking ultrathin films of PbS, PbSe, and PbTe as examples, that the diffusivity–mobility ratio increases with increasing electron concentration and decreasing film thickness in various oscillatory manners. The magnetic field and the quantum wire structure enhance the numerical values of the same ratio. We have suggested an experimental method of determining the Einstein relation in degenerate materials having arbitrary dispersion laws from the measurement of thermoelectric power in the presence of a large magnetic field. In addition, the corresponding well‐known results for relatively wide‐gap quantum confined materials in the absence of the magnetic field have been obtained as special cases of our generalized formulations, under certain limiting conditions.