5 research outputs found
Theory of Transmission through disordered superlattices
We derive a theory for transmission through disordered finite superlattices
in which the interface roughness scattering is treated by disorder averaging.
This procedure permits efficient calculation of the transmission thr ough
samples with large cross-sections. These calculations can be performed
utilizing either the Keldysh or the Landauer-B\"uttiker transmission
formalisms, both of which yield identical equations. For energies close to the
lowest miniband, we demonstrate the accuracy of the computationally efficient
Wannier-function approximation. Our calculations indicate that the transmission
is strongly affected by interface roughness and that information about scale
and size of the imperfections can be obtained from transmission data.Comment: 12 pages, 6 Figures included into the text. Final version with minor
changes. Accepted by Physical Review
CO2 laser-induced long-period fibre gratings: spectral characteristics, cladding modes and polarisation independence
Axial rotation dependence of resonances in curved CO2-laser-induced long-period fibre gratings
Design of electron band pass filters for electrically biased finite superlattices
We design optimal band pass filters for electrons in semiconductor heterostructures, under a uniform applied electric field. The inner cells are chosen to provide a desired transmission window. The outer cells are then designed to transform purely incoming or outgoing waves into Bloch states of the inner cells. The transfer matrix is interpreted as a conformal mapping in the complex plane, which allows us to write constraints on the outer cell parameters, from which physically useful values can be obtained