Weak localization in InSb thin films heavily doped with lead

Abstract

The paper reports on the investigations of the weak localization (WL) effects in 3D polycrystalline thin films of InSb. The films are closely compensated showing the electron concentration n>10^{16} cm^{-3} at the total concentration of the donor and acceptor type structural defects >10^{18} cm^{-3}. Unless Pb-doped, the InSb films do not show any measurable or show very small WL effect at 4.2 K. The Pb-doping to the concentration of the order of 10^{18} cm^{-3} leads to pronounced WL effects below 7 K. In particular, a clearly manifested SO scattering is observed. From the comparison of the experimental data on temperature dependence of the magnetoresistivity and sample resistance with the WL theory, the temperature dependence of the phase destroying time is determined. The determination is performed by fitting theoretical terms obtained from Kawabata's theory to experimental data on magnetoresistance. It is concluded that the dephasing process is connected to three separate interaction processes. The first is due to the SO scatterings and is characterized by temperature-independent relaxation time. The second is associated with the electron-phonon interaction. The third dephasing process is characterized by independent on temperature relaxation time tau_c. This relaxation time is tentatively ascribed to inelastic scattering at extended structural defects, like grain boundaries. The resulting time dephasing time shows saturation in its temperature dependence. The temperature dependence of the resistance of the InSb films can be explained by the electron-electron interaction for T2 K.Comment: 15 pages with 5 figure