Realistic multiband k.p approach from ab initio and spin-orbit coupling effects of InAs and InP in wurtzite phase

摘要

Semiconductor nanowires based on non-nitride III-V compounds can besynthesized under certain growth conditions to favor the appearance of wurtzitecrystal phase. Despite the reports in literature of ab initio band structuresfor these wurtzite compounds, we still lack effective multiband models andparameter sets that can be simply used to investigate physical properties ofsuch systems, for instance, under quantum confinement effects. In order toaddress this deficiency, in this study we calculate the ab initio bandstructure of bulk InAs and InP in wurtzite phase and develop an 8$\times$8 k.pHamiltonian to describe the energy bands around $\Gamma$ point. We show thatour k.p model is robust and can be fitted to describe the important features ofthe ab initio band structure. The correct description of the spin splittingeffects that arise due to the lack of inversion symmetry in wurtzite crystals,is obtained with the $k$-dependent spin-orbit term in the Hamiltonian, oftenneglected in the literature. All the energy bands display a Rashba-like spintexture for the in-plane spin expectation value. We also provide the density ofstates and the carrier density as functions of the Fermi energy. Alternatively,we show an analytical description of the conduction band, valid close to$\Gamma$ point. The same fitting procedure is applied to the 6$\times$6 valenceband Hamiltonian. However, we find that the most reliable approach is the8$\times$8 k.p Hamiltonian for both compounds. The k.p Hamiltonians andparameter sets that we develop in this paper provide a reliable theoreticalframework that can be easily applied to investigate electronic, transport,optical, and spin properties of InAs- and InP-based nanostructures.