Effective mass and $g$-factor of two-dimensional HgTe $\Gamma_8$-band electrons: Shubnikov–de Haas oscillations

We present a study of Shubnikov-de Haas (SdH) oscillations at temperatures of (2.2–10) K in magnetic fields up to 2.5 T in the HgCdTe/HgTe/HgCdTe heterostructure for a wide (20.3 nm) HgTe quantum well with an inverted energy band structure. The analysis of the temperature dependence of SdH amplitude in weak fields, in a region of doubly degenerate magnetoresistance peaks, led us to the value of effective electron mass $m_c/m_0$ = (0.022 $\pm$ 0.002) which is about half the theoretical estimates. But in a region of higher magnetic fields, for nondegenerate magnetoresistance peaks, we confidently have $m_c/m_0$ = (0.034 $\pm$ 0.003) in good agreement both with the theoretical estimation and with our experimental results on the analysis of activation transport under quantum Hall effect regime. The reasons for this discrepancy are discussed.