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HL: Fachverband Halbleiterphysik

HL 64: Quantum Wires: Transport

HL 64.6: Vortrag

Mittwoch, 16. März 2011, 17:45–18:00, POT 251

Efficient simulation of cylindrical nanowire heterostructures by means of the R-matrix formalism — •Paul Nicolae Racec, Hans-Christoph Kaiser, and Klaus Gärtner — Weierstrass Institute, Mohrenstr. 39, 10117 Berlin, Germany

The Landauer-Bütiker formalism is a well established method for describing ballistic transport in semiconductor nanostructures in the framework of scattering theory. However, direct 2d and 3d simulations of complex heterostructures with this method require a considerable computational effort. The R-matrix formalism is a potent means to reduce the computational costs to the solution of an eigenproblem for the electronic Schrödinger operator in effective mass approximation on a bounded domain with mixed Dirichlet and Neumann boundary conditions. For complex heterostructures this eigenproblem has to be solved numerically and provides the real Wigner-Eisenbud eigenfunctions and -energies. Our numerical approach is based upon a Delaunay triangulation of the rotational symmetric device domain and a finite volume discretization. Thus we can describe any complex geometry and take into account the inhomogeneities and the anisotropy of material properties, like the effective mass. The Wigner-Eisenbud functions and energies are used further on to compute explicitly the energy dependent scattering matrix elements and wave functions which feed into the Landauer-Bütiker formalism. We present results (tunneling coefficients and resonant scattering states) for cylindrical nanowires with embedded substructures like double barriers, quantum dots or quantum rings.