Search

We theoretically study the spin-polarized electron transport properties of a quantum wire under irradiation of a transversely polarized external electromagnetic (EM) wave in the presence of Rashba spin-orbit interaction (SOI). Using the free-electron model and the scattering matrix approach, we show that spin polarization is independent on the EM frequency and the electron incident energy when Rashba SOI is weak, while it is strongly dependent on the EM frequency and the incident energy when Rashba SOI is comparatively strong. In addition, an unusual step-structure appears in the electronic transmission probability as the incident energy increases to a threshold value when a coherent EM field is applied. We demonstrate that the first effect comes from Rashba subband intermixing and the latter comes from inelastic scattering of electrons with lateral photons through intersubband transitions.

We study the nanoelectromechanics in a quantum wire connecting two reservoirs irradiated under an external terahertz (THz) electromagnetic field. Using the free-electron model at ballistic regime we calculated the two-level electron wavefunction and the Rabi oscillation of electron probability between the two levels. Using a statistical operator we calculated the nanoelectronic force in the wire. The result consists of two terms, which corresponds to the case with or without external field. The term without field parameter is consistent with the existing experimental observation and theoretical calculation, and the other term from the external field can be explained by the quantum coherent theory.

Using a transformation of hyperbolic function, the Schr?dinger equation with reflection-less potential well is transformed into an associated-Legendre equation. Then both bound and scattering state eigenfunctions are expressed in terms of associated-Legendre polynomials and functions respectively. The exact solutions obtained in this paper are more general and systematic than some asymptotic solutions or solutions of reflectionless potential with special parameters in literatures. The normalization of the scattering state is discussed in detail.

In the reference [1] , we have given the exact solutions of both bound and scattering sfa-tes for one dimensional Schr?dmger equation with potential V(x)=-N(N +1l)sech2x in the case of arbitrary positive integer N. In the present work we extend the results of [1] to three dimensional case, and find some physical significance which is different from that in one di-mensional case.