Surface plasmon polaritons are a promising basis for nanoscale photonic devices because they can concentrate light below the diffraction limit and allow for strong light-matter interactions. We demonstrate an efficient nanoscale electrical detector for propagating plasmons, an essential component for integrated plasmonic nanocircuits. Our technique is based on the near-field coupling between guided plasmons and a nanowire field-effect transistor. The intrinsic detection efficiencies of our detectors are approximately 0.1 electrons/plasmon, and the signal can be amplified up to 50 electrons per plasmon using a plasmonic gating effect. Finally, we demonstrate that this near-field circuit can be used to efficiently detect the emission from a single quantum dot that is directly coupled to a plasmonic waveguide
The second part of this thesis studies phase transitions in nanowires. First, we report observation of a current-driven metal-insulator phase oscillation in two-terminal devices incorporating individual WxV 1-xO2 nanobeams. The frequency of the phase oscillation reaches above 5 MHz for ∼1-mum-long devices. The M-I phase oscillation occurs through the axial drift of a single M-I domain wall driven by Joule heating and the Peltier effect. Second, we characterize the stability of the superconducting dissipationless and resistive states in single-crystalline NbSe2 nanoribbons by transport measurements. Current-driven electrical measurements show voltage steps, indicating the nucleation of phase-slip structures. Well below the critical temperature, the position of the voltage steps exhibits a sharp, periodic dependence as a function of magnetic field. We discuss this phenomenon in the context of two possible mechanisms: the interference of the order parameter and the periodic rearrangement of the vortex lattice within the nanoribbon
Taken together, these results show that single emitters and single domains can be detected electrically. They are a step towards understanding and controlling nanoscale physical processes at the fundamental component level
