Band structure of semimagneticHg1−yMnyTequantum wells

Abstract

The band structure of semimagnetic Hg1−yMnyTe/Hg1−xCdxTe type-III quantum wells has been calculated using eight-band k · p model in an envelope function approach. Details of the band structure calculations are given for the Mn free case (y = 0). A mean field approach is used to take the influence of the sp − d exchange interaction on the band structure of QW's with low Mn concentrations into account. The calculated Landau level fan diagram and the density of states of a Hg0.98Mn0.02Te/Hg0.3Cd0.7Te QW are in good agreement with recent experimental transport observations. The model can be used to interpret the mutual influence of the two-dimensional confinement and the sp−d exchange interaction on the transport properties of Hg1−yMnyTe/Hg1−xCdxTe QW's.

Electron relaxation and mobility in the inverted band quantum well CdTe/Hg1-xCdxTe/CdTe

“…Nevertheless, the k  = 0 wave functions correctly describe many principal features of the band structure under consideration, particularly, they correctly describe the localization of electrons in the well and selection rules for interband transitions. Moreover, the energy spectra obtained in terms of the envelope functions approach [17] behave in the same way as such spectra obtained in terms of the 88 kp method [37]. In our calculations, we use nonparabolic dispersion law in order to describe correctly the energy dependence of the density of states.…”

Spin properties of Hg1–xCdx Te/CdTe quantum wells

“…(8) reduces to standard expressions for energy levels in an infinite quantum well: Figure 3 shows the subband edges originating from bulk conduction and valence bands as a function of the energy gap calculated with Eq. (8). It is seen that in the inversion region, where the bulk bands cross over, the 2D conduction and light-mass related subbands repel each other.…”

“…(8) is an approximate, it shows only the general trend and does not give the crossing of E1 and H1 subbands in Fig. 2 that, in fact, occurs in HgTe/CdTe QWs at the considered energies [8]. The crossing may be obtained if the full determinant that results from Eq.…”

“…This means that their spin precession trajectories are elliptical rather than circular. The confinement of free electrons and holes between the barriers, for example in HgTe/CdTe quantum well, will result in spatial energy quantization, which due to strong interaction between inverted energy subbands gives rise to new interesting properties [6][7][8]. Furthermore, in the inverted QWs the Rashba spin-splitting of up to 30 meV has been measured, which is almost an order of magnitude larger than in A 3 B 5 compounds.…”

Циклотронный резонанс дираковских фермионов в квантовых ямах InAs/GaSb/InAs

“…Зонная структура систем с трехслойными КЯ InAs/ GaSb/InAs, с ограничительными барьерами AlSb рассчи-тывалась с использованием 8-зонного k · p-гамильтониа-на в качестве оператора кинетической энергии с гранич-ными условиями из работы [10]. В используемом гамиль-тониане k · p-взаимодействие зоны проводимости Ŵ 6 с валентными зонами Ŵ 8 и Ŵ 7 рассматривается точно, а взаимодействие с остальными зонами учитывается по теории возмущений.…”