Activation conductivity in HgTe/CdHgTe quantum wells at integer Landau level filling factors: Role of the random potential

Resumo

Shubnikov-de Haas oscillations are studied in 8-nm-wide HgTe/CdHgTe quantum wells with an electron concentration of (1.7–13) × 10¹¹ cm^–2 in the temperature range from 1.6 to 40 K. The gaps between Landau levels and the quantum relaxation time are determined from the temperature dependence of the oscillation amplitude at integer filling factors. The experimental gap values are found to be in good agreement with the results of the single-particle calculation of the level energies using the 8-band Kane model. The experimental widths of the density of states are indicative of profound screening of the exchange interaction in HgTe/CdHgTe quantum wells.