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Effect of electronic interactions in networks of weakly disordered metallic wires
Christophe Texier (Université Paris-Sud)
14.01.2011 at 10:15
Quantum interferences of reversed trajectories are responsible for a
small contribution to the conductivity, known as the "weak localization
correction" (WL). From the experimental point of view, the study of the
WL provides an efficient tool in order to probe phase coherence in weakly
disordered metals. In practice, the WL is identified through its
magnetic field dependence: the conductance of a network made of
equivalent rings presents oscillations as a function of the flux with
period $h/2e$, known as Al'tshuler-Aronov-Spivak (AAS) oscillations.
Due to the non-local nature of quantum transport, these oscillations
depend on the precise geometry of the system.
At low temperature, electron-electron interaction provides the dominant
mechanism that limits phase coherence and controls the WL.
In networks, the decoherence is sensitive to the nontrivial geometry
of the system. I will discuss the case of several networks (chains of
rings, square networks) and cylinders. I will identified the several
length scales characterizing the problem.
Another quantum correction to transport coefficients due to
electron-electron interaction is the Altshuler-Aronov correction.
Contrary to the WL, this contribution is incoherent, controlled by the
thermal length (i.e. the temperature). I will analyze its dependence
in a large square network.
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