Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster 1

HL 13.22: Poster

Montag, 26. März 2007, 15:00–17:30, Poster A

A block-tridiagonalization algorithm for quantum transport calculations — •Michael Wimmer and Klaus Richter — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg

There is a great variety of numerical algorithms for the calculation of coherent quantum transport. Usually, these algorithms have two things in common: They are based on tight-binding Hamiltonians and, in order to work efficiently, the Hamiltonian matrix must be in block-tridiagonal form. In general, this form is optimal - i.e. the algorithm runs most efficiently - if the blocks are as small as possible and equally sized. Even for very symmetric structures it can be difficult to construct the optimal form by hand, for complex structures it is even more difficult.

We present an algorithm based on heuristic graph partitioning techniques that brings a Hamiltonian matrix into an optimal block-tridiagonal form. It can be used as input for serial and parallel transport algorithms. Based upon that algorithm and the recursive Green's function method, we have developed a code for coherent transport calculations that is suited for any tight-binding model and can also deal with multiterminal structures.