Spin splittings in the n -HgTe/CdxHg1−xTe(013) quantum well with inverted band structure

An effective g  -factor (g*g*) in the conduction band of an inverted band structure of the (0 1 3)-oriented 20 nm wide HgTe quantum well is measured by different ways: from the structure of the Shubnikov–de Haas oscillations and the quantum Hall effect, from their activation development with temperature; from the coincidence effect in tilted magnetic fields and from the activation analysis of the coincidence features taken at constant temperature as a function of the parallel magnetic field component at the fixed filling factor. Probably we present the first observation of the coincidence effect in the regime of the quantum Hall effect that is possible due to g*m*/m0>1g*m*/m0>1 in the investigated material. Shown is that while under pure perpendicular magnetic fields the obtained |g*||g*| value is in the range of 50–6050–60, considerably smaller and much smaller values are deduced from the experiments that include parallel field component. This could be described by the g  -factor anisotropy of g⊥/g||≈5g⊥/g||≈5. The main source of this giant anisotropy is assumed to be a quasi-two-dimensional nature of the spin splittings in the HgTe conduction band of p-like character although the zero field spin splittings due to strong spin–orbit interaction should also be considered.