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FIZIKA A 3 (1994) 3, 155-176
 
THE EINSTEIN RELATION IN SUPERLATTICES OF NON-PARABOLIC SEMICONDUCTORS
WITH GRADED INTERFACES UNDER MAGNETIC QUANTIZATION
KAMAKHYA P. GHATAK and SAMBHU N. BANIK*
Department of Electronic Science, University of Calcutta, University College of
Science and Technology, 92, Acharya Prafulla Chandra Road, Calcutta - 700 009, India
*Department of Physics, Dandirhat Nagendrakumar Uchcha Siksha Niketan, P. O.
Dandirhat, Dt. North 24 Parganas, West Bengal, India
Received 15 December 1992
Revised manuscript received 28 July 1994
We study the Einstein relation under magnetic quantization in III-V, II-VI,
PbSnTe/PbTe, strained layer and HgTe/CdTe superlattices with graded interfaces and compare
the same with that of the corresponding bulk specimens of the constituent materials. It is
found, taking GaAs/Ga1-xAlxAs, CdS/CdTe, PbTe/PbSnTe, InAs/GaSb and
HgTe/CdTe superlattices with graded interfaces as examples, that the Einstein relation
exhibits oscillatory dependence with the inverse quantizing magnetic field due to the
Shubnikov-de Haas effect, and increases with increasing electron concentration in an
oscillatory manner in all the cases. The ratio of diffusivity to mobility in graded
superlattices is greater than that of constituent bulk materials. The oscillations in
HgTe/CdTe superlattices show up much more significantly as compared to other systems. In
addition, we have suggested an experimental method of determining the Einstein relation in
degenerate materials having arbitrary dispersion laws.
UDC 538.915
PACS 71.25.Tn, 73.20.Dx
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