The energy spectrum of charge carriers in thin films differs from that in bulk specimens. This distinction shows itself in the quantum size effects. F o r the first time quantum size effects were found in thin B i films /l/.The authors of /1/ observed oscillations of the kinetic coefficients in dependence on the film thickness. These oscillations were due to sharp changes in the density of states when the energy of quantized levels was equal to the Fermi energy of charge carriers.It is well-known that the density of states is governed by the dispersion relation. For example, in the case of an ellipsoidal non-parabolic spectrum /2/ the density of electron states (per unit surface) in Bi films has the following form /3/:Here axis 1 is directed along the binary axis, axis 2 along the elongation of the constant energy surface, axis 3 along the trigonal axis (we neglected the tilt angle 'p%6 of the axis 3 t o the trigonal axis), g, = 2 is the spin degeneracy, gv = 3 is the valley degeneracy, n = 1, 2 . . . is the size 0 quantdm number, a = 1/E (E is the band g g m, side function, d is the film thickness, and EnWe must note that formula (1) is correct for the case when theJfilm a plane is normal to the trigonal axis. In the present note we restrict ourselves to this case only for simplicity.As it is seen from (1) the density of states is a step-like function of energy.The expression of N(E) for an ellipsoidal parabolic spectrum may be 1) prospekt Narimanova, 370143 Baku, USSR.
Measurements of the lattice thermal conductivity between 90 and 300 O K of a series of GaSb-Ge alloys indicate that there is an additional thermal resistivity in the two-phase region which can be attributed to grain boundary scattering of phonons. The results in the single phase region are compared with the theories of Klemens, Callaway, and Berman.
In /1/ the density of electron states g( E ) in thin B i film is calculated for the c a s e when the energy spectrum is described by the Abrikosov dispersion relation /2/. It is shown that g( E ) has logarithmic singularities in the presence of size quantization. On the b a s i s of this fact it is assumed that for the Abrikosov spectrum the quantum size oscillations of kinetic coefficients are more pronounced than for the standard o r the Kane spectra. In the present note we report the results of calculations of the thermopower in a classical strong magnetic field which confirm this assumption.
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