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TT: Fachverband Tiefe Temperaturen

TT 58: Transport: Poster Session

TT 58.30: Poster

Wednesday, March 9, 2016, 15:00–18:30, Poster D

Improved auxiliary-mode approach to time-dependent electron transport — •Bogdan Popescu and Alexander Croy — Max Planck Institut for the Physics of Complex Systems

The theoretical description of time-resolved phenomena in nanoscale devices remains a very challenging task. Several formalisms are available, but efficient approaches for general-purpose computations are still under investigation. In [1] it was proposed to use an auxiliary-mode expansion of the self-energies arising in the time-dependent non-equilibrium Greens function (TDNEGF) formalism. To this end the Fermi function and the level-width function are expanded in terms of simple poles (Lorentzians). This procedure converts the integro-differential equation for the reduced density-matrix into a set of coupled differential equations for auxiliary matrices.

In this contribution we present an improved version of the auxiliary-mode approach, where the auxiliary matrices are replaced by vectors or scalars. This drastically reduces the computational effort and memory requirement of the method. We demonstrate the method using a molecular wire and graphene nanoribbons as examples.
A. Croy and U. Saalmann, PRB 80, 245311 (2009)