Nonparabolicity effects and the spin–split electron dwell time in symmetric III–V double-barrier structures

Abstract

We start from the fourth order nonparabolic and anisotropic conduction band bulk dispersion relation to obtain an one-band effective Hamiltonian which we apply to an AlGaSb symmetric doublebarrier structure with resonant energies significantly (more than 200meV) above the well bottom. The spin-splitting is described by the k 3 Dresselhaus spin-orbit coupling term modifying only the effective mass of the spin eigenstates in the investigated structure. Apart from the bulk-like resonant energy shift due to the band nonparabolicity, we obtain a substantial shift depending on the choice of boundary conditions for the envelope functions at interfaces between different materials. The shift of resonant energy levels leads to the change of spin-splitting and the magnitude of the dwell times. We attempt to explain the influence of both the nonparabolicity and boundary conditions choice by introducing various effective masses.

Origin of Rashba splitting in the quantized subbands at the Bi2Se3surface

“…In addition, the M-shape of the VSBs, which is imposed by the VB dispersion, is expected to further decrease the Rashba splitting. Nonparabolicity effects have been found to reduce considerably the Rashba splitting especially for semiconductors with small bandgap, as it is the case for Bi 2 Se 3 [45][46][47].…”