Посилання:Magnetotransport studies of SiGe-based p-type
heterostructures: problems of the effective mass
determination / I.B. Berkutov, V.V. Andrievskii, Yu.F. Komnik, Yu.A. Kolesnichenko, R.J.H. Morris, D.R. Leadley, O.A. Mironov // Физика низких температур. — 2012. — Т. 38, № 12. — С. 1455–1463. — Бібліогр.: 26 назв. — англ.
Підтримка:The authors thank to T. Hackbarth (Daimler AG Forschungszentrum,
89081 Ulm, Germany), for the MBE
growth/fabrication of the sample “C”. Measurements were
made at the Nanosilicon Group, Department of Physics,
University of Warwick, Coventry, UK, and partially at the
International Laboratory of High Magnetic Fields and Low
Temperatures, Wroclaw, Poland.
The Shubnikov–de Haas oscillations method of the effective mass extraction was illustrated by the magnetotransport
properties investigation of two-dimensional hole gas in Si₁₋xGex (x = 0.13, 0.36, 0.95, 0.98) QWs. We
have found that for certain samples our data cannot be fitted to standard theoretical curves in which the scattering
of charge carriers is described by conventional Dingle factor. It is demonstrated that reasons of deviations of
the experiment from the theory are as follows; (i) influence of the spin splitting on amplitude of SdH oscillations
maxima; (ii) extra broadening of the Landau levels attributed to existence of inhomogeneous distribution of the
carrier concentration; (iii) the influence of the concurrent existence of short and long-range scattering potentials;
(iv) the population of second energy level in the quantum well. The ways to calculate the effective masses m* of
holes in all cases are presented and values of m* are found for studied heterostructures.