Jungiusstr. 9, Seminarraum 6
SFB 668 - Sonder-Kolloquium
Prof. Andreas Komnik (Universität Heidelberg):
Bistability in molecular quantum dots: numerics vs analytical results
Electrically contacted molecules might potentially become the basic building blocks of future nanoelectronic circuitry. The paradigm for description of their transport properties is a single fermionic level coupled to a local harmonic mode and external metallic electrode(s). This model is usually referred to as Holstein-Anderson or molecular quantum dot model. Within the framework of a very simple adiabatic approximation it can be shown to possess a regime of bistability, in which the current-voltage characteristics of the system turns out to develop a hysteresis. However, the precise parameter window, in which this kind of behaviour is possible is very difficult to identify. This is the central issue of the presentation, in which the problem is going to be discussed using recent results of numerical simulations with the help of conventional and diagrammatic Monte Carlo techniques as well as multilayer multiconfiguration time-dependent Hartree method. It will be shown, that the numerical results can be understood by an explicit mapping of the low energy effective theory to that of a well-understood single channel Kondo model.