Effective model for the electronic and optical properties of stanene

Abstract

The existence of several 2D materials with heavy atoms has recently been demonstrated. The electronic and optical properties of these materials can be accurately computed with numerically intensive density functional theory methods. However, it is desirable to have simple effective models that can accurately describe these properties at low energies. Here we present an effective model for stanene that is reliable for electronic and optical properties for photon energies up to 1.1 eV. For this material, we find that a quadratic model with respect to the lattice momentum is the best suited for calculations based on the bandstructure, even with respect to band warping. We also find that splitting the two spin-ẑ subsectors is a good approximation, which indicates that the lattice buckling can be neglected in calculations based on the bandstructure. We illustrate the applicability of the model by computing the linear optical injection rates of carrier and spin densities in stanene. Our calculations indicate that an incident circularly polarized optical field only excites electrons with spin that matches its helicity.

A Perspective on Recent Advances in 2D Stanene Nanosheets

“…Interestingly, stanene exhibits excitation of the spin match carrier helicity upon incidence of circularly polarized light, similar to silicene, and, hence, the spin induced photocurrent can be useful in spintronic applications. [121,122] Anisotropy behavior has been observed in pristine stanene, stanene nanoribbons, and functionalized stanene structures. With narrowing of the width of stanene nanoribbon structures, the bandgap opens up, due to quantum confinement.…”

“…Three absorption band have been observed at 88 meV, 0.472 eV, and 0.808 eV, due to bandgap energy at K‐K′, the Γ‐point, and the second valence band transitions, respectively. Interestingly, stanene exhibits excitation of the spin match carrier helicity upon incidence of circularly polarized light, similar to silicene, and, hence, the spin induced photocurrent can be useful in spintronic applications . Anisotropy behavior has been observed in pristine stanene, stanene nanoribbons, and functionalized stanene structures.…”

Quantum interference control of carriers and currents in zinc blende semiconductors based on nonlinear absorption processes

“…The free parameters of the model are the energies E A , the matrix elements of the spin-orbit term ∆ AB , and the matrix elements of the momentum operator P AB . Since the basis for the states is the same at every k point [45], the corresponding 2 × 2 matrices corresponding to the velocity operator A|v|B are diagonal in the spin sector,…”