The spin-splitting energies of the conduction band for ideal wurtzite materials are calculated within the nearest-neighbor tight-binding method. It is found that ideal wurtzite bulk inversion asymmetry yields not only a spin-degenerate line ͑along the k z axis͒ but also a minimum-spin-splitting surface, which can be regarded as a spin-degenerate surface in the form of bk z 2 − k ʈ 2 =0 ͑b Ϸ 4͒ near the ⌫ point. This phenomenon is referred to as the Dresselhaus effect ͑defined as the cubic-ink term͒ in bulk wurtzite materials because it generates a term ␥ wz ͑bk z 2 − k ʈ 2 ͒͑ x k y − y k x ͒ in the two-band k • p Hamiltonian.

The electronic Landau level structures of the symmetric Alsb-Al x Ga 12x Sb-InAs-Al x Ga 12x Sb-AlSb quantum wells are investigated within a six-band k ? p finite difference method. We demonstrated that the conduction-valence Landau level mixing can yield a significant spin splitting for the InAs conduction-band electrons and therefore produce a prominent electron double-line structure with a nearly field-independent energy separation in the cyclotron-resonance spectra. This mixing effect can also yield strong oscillations in the electron cyclotron-resonance mass, amplitude, and linewidth. [S0031-9007(96)01082-4]

We have confirmed the k-dependent spin splitting in wurtzite Al x Ga 1-x N/GaN heterostructures. Anomalous beating pattern in Shubnikov-de Haas measurements arises from the interference of Rashba and Dresselhaus spin-orbit interactions. The dominant mechanism for the k-dependent spin splitting at high values of k is attributed to Dresselhaus term which is enhanced by the ∆ C1 -∆ C3 coupling of wurtzite band folding effect.

A new mechanism (∆ C1 -∆ C3 coupling) is accounted for the spin splitting of wurtzite GaN, which is originated from the intrinsic wurtzite effects (band folding and structure inversion asymmetry). The band-folding effect generates two conduction bands (∆ C1 and ∆ C3 ), in which p-wave probability has tremendous change when k z approaches anti-crossing zone. The spin-splitting energy induced by the ∆ C1 -∆ C3 coupling and wurtzite structure inversion asymmetry is much larger than that evaluated by traditional Rashba or Dresselhaus effects. When we apply the coupling to GaN/AlN quantum wells, we find that the spin-splitting energy is sensitively controllable by an electric field. Based on the mechanism, we proposed a p-wave-enhanced spin-polarized field effect transistor, made of In x Ga 1-x N/In y Al 1-y N, for spintronics application. _____________________

Spin-splitting energies of wurtzite AlN and InN are calculated using the linear combination of atomic orbital method, and the data are analyzed utilizing the two-band k • p model. It is found that in the k • p scheme, a spin-degenerate surface exists in the wurtzite Brillouin zone. Consequently, the D'yakonov-Perel' spin relaxation mechanism can be effectively suppressed for all spin components in the ͓001͔-grown wurtzite quantum wells ͑QWs͒ at a resonant condition through application of appropriate strain or a suitable gate bias. Therefore, wurtzite QWs ͑e.g., InGaN/AlGaN and GaN/ AlGaN͒ are potential structures for spintronic devices such as the resonant spin lifetime transistor.