Electronic properties of semiconductors
Electron-phonon processes in semiconductors at low temperatures
S. A. Aliev Institute of Physics Azerbaijan Academy of Sciences
Abstract:
The thermal conductivity and thermopower are simultaneously studied in the semiconductors HgSe, HgTe, InP, GaAs, Cd
$_x$H
$_{1-x}$Te, and Ag
$_2$S in which the effect of electron drag by phonons was detected at low temperatures
$T$. It is found that
$x$ = 1–3 in the dependences
$K_{\mathrm{ph}}\propto T^{-x}$. It is shown that the underestimated values of
$x$ are caused by phonon scattering at certain defects. It is also found that the maxima of
$K_{\mathrm{ph}}(T)$ and
$\alpha_{\mathrm{ph}}(T)$ coincide in all studied crystals, except for Ag
$_2$S. For the first time, it is found that the strong effect
$\alpha_{\mathrm{ph}}\propto T^{-3}$ is observed in Ag
$_2$S, the
$\alpha_{\mathrm{ph}}$ maximum is at
$T$ = 16 K, and the
$K_{\mathrm{ph}}$ maximum is at 27 K. The results obtained are in agreement with Callaway and Herring theory. The effect of magnetic field on the drag thermopower
$\alpha_{\mathrm{ph}}(T)$ in
$n$-Cd
$_x$Hg
$_{1-x}$Te (in which the strong dependence
$\alpha_{\mathrm{ph}}\propto T^{-3}$ and the strong effect of the magnetic field on it are detected) is considered for the first time. The results are compared with the Askerov theory. The force parameter
$A_{\mathrm{ph}}(\varepsilon)$ of the drag effect and its dependence on magnetic field are determined.
Received: 09.04.2013
Accepted: 06.06.2013
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