Four-terminal resistance of a quantum wire with weakly invasive contacts (invited talk)

CARLOS M. NAÓN

Buenos Aires

Congreso; Autumn College on Non-Equilibrium Quantum Systems; 2011

International Centre for Theoretical Physics, FCE, UBA

One of the central issues in quantum transport is the actual nature of the resistance in a mesoscopic device. It is well known that, in the absence of impurities, the two-terminal conductance of a single-channel quantum wire is given by the universal conductance quantum $G_0=e^2/h$. Thus, the two-terminal resistance depends only on the nature of the contacts through which the driving voltage is applied. It becomes then natural to consider an alternative physical concept able to describe the resistive behavior of the sample. To this end, it is specially useful the concept of multi-terminal resistance. In particular, for the four-terminal resistance $R_{4t}$, the theory predicts the possibility of $R_{4t}