Absence of magneto-intersubband scattering inn-type HgTe quantum wells

Abstract

Magneto-intersubband scattering (MIS), which is a general feature in III-V semiconductor heterostructures with two occupied subbands, is demonstrated to be absent in both asymmetric and symmetric type-III HgTe quantum wells (QW's). The analysis of the temperature dependence of Shubnikov--de Haas (SdH) oscillations and their fast Fourier transforms, together with the excellent agreement between the measured longitudinal resistivity and the calculated oscillations in the density of states in a magnetic field within the framework of an $8\ifmmode\times\else\texttimes\fi{}8$ $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ model, completely rule out the MIS effect. The absence of the MIS effect in HgTe QW's is ascribed to a much more complex and irregular Landau level alignment which suppresses the intersubband scattering rate. A natural consequence of the absence of MIS is that the Rashba spin splitting can be properly identified from the SdH oscillations in a perpendicular magnetic field and at a constant temperature, in contrast to the recent findings for InAs QW's.