Conducting nanowires possess remarkable physical properties unattainable in bulk materials. However our understanding of their transport properties is limited by the difficulty of connecting them electrically. In this Letter we investigate phototrans
port in both bulk silicon and silicon nanowires using a superconducting multimode resonator operating at frequencies between 0.3 and 3 GHz. We find that whereas the bulk Si response is mainly dissipative, the nanowires exhibit a large dielectric polarizability. This technique is contactless and can be applied to many other semiconducting nanowires and molecules. Our approach also allows to investigate the coupling of electron transport to surface acoustic waves in bulk Si and to electro-mechanical resonances in the nanowires.
We have tuned in situ the proximity effect in a single graphene layer coupled to two Pt/Ta superconducting electrodes. An annealing current through the device changed the transmission coefficient of the electrode/graphene interface, increasing the pr
obability of multiple Andreev reflections. Repeated annealing steps improved the contact sufficiently for a Josephson current to be induced in graphene.
We investigate weak localization in metallic networks etched in a two dimensional electron gas between $25:$mK and $750:$mK when electron-electron (e-e) interaction is the dominant phase breaking mechanism. We show that, at the highest temperatures,
the contributions arising from trajectories that wind around the rings and trajectories that do not are governed by two different length scales. This is achieved by analyzing separately the envelope and the oscillating part of the magnetoconductance. For $Tgtrsim0.3:$K we find $Lphi^mathrm{env}propto{T}^{-1/3}$ for the envelope, and $Lphi^mathrm{osc}propto{T}^{-1/2}$ for the oscillations, in agreement with the prediction for a single ring cite{LudMir04,TexMon05}. This is the first experimental confirmation of the geometry dependence of decoherence due to e-e interaction.
