Tailoring palladium nanocontacts by electromigration

Electromigration is employed in nanoelectronics for transforming narrow metallic wires into electrodes separated by a few nanometers gap. In this work, we fabricate either nanoconstrictions or nanogap electrodes by performing electromigration in palladium nanowires. The device resistance and the cross section of the initial nanowires allow us to regulate the conditions for transforming deterministically each nanowire in a specific final device. The resulting samples show unique electrical transport characteristics and could be used in multiple nanoelectronics research applications, from ballistic transport to electrodes for single molecular devices.Fil: Arzubiaga, Libe. CIC nanoGUNE; EspañaFil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Llopis, Roger. CIC nanoGUNE; EspañaFil: Casanova, Félix. CIC nanoGUNE; España. Basque Foundation for Science; EspañaFil: Hueso, Luis E.. CIC nanoGUNE; España. Basque Foundation for Science; Españ

Real-Space Mapping of Fano Interference in Plasmonic Metamolecules

An unprecedented control of the spectral response of plasmonic nanoantennas has recently been achieved by designing structures that exhibit Fano resonances. This new insight is paving the way for a variety of applications, such as biochemical sensing and surface-enhanced Raman spectroscopy. Here we use scattering-type near-field optical microscopy to map the spatial field distribution of Fano modes in infrared plasmonic systems. We observe in real space the interference of narrow (dark) and broad (bright) plasmonic resonances, yielding intensity and phase toggling between different portions of the plasmonic metamolecules when either their geometric sizes or the illumination wavelength is varied.Fil: Alonso Gonzalez, Pablo. No especifíca;Fil: Schnell, Martin. No especifíca;Fil: Sarriugarte, Paulo. No especifíca;Fil: Sobhani, Heidar. Rice University; Estados UnidosFil: Wu, Chihhui. University of Texas at Austin; Estados UnidosFil: Arju, Nihal. University of Texas at Austin; Estados UnidosFil: Khanikaev, Alexander. University of Texas at Austin; Estados UnidosFil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Albella, Pablo. Consejo Superior de Investigaciones Científicas; EspañaFil: Arzubiaga, Libe. No especifíca;Fil: Casanova, Felix. No especifíca;Fil: Hueso, Luis E.. No especifíca;Fil: Nordlander, Peter. Rice University; Estados UnidosFil: Shvets, Gennady. University of Texas at Austin; Estados UnidosFil: Hillenbrand, Rainer. No especifíca

Visualizing the near-field coupling and interference of bonding and anti-bonding modes in infrared dimer nanoantennas

We directly visualize and identify the capacitive coupling of infrared dimer antennas in the near field by employing scattering-type scanning near-field optical microscopy (s-SNOM). The coupling is identified by (i) resolving the strongly enhanced nano-localized near fields in the antenna gap and by (ii) tracing the red shift of the dimer resonance when compared to the resonance of the single antenna constituents. Furthermore, by modifying the illumination geometry we break the symmetry, providing a means to excite both the bonding and the >dark> anti-bonding modes. By spectrally matching both modes, their interference yields an enhancement or suppression of the near fields at specific locations, which could be useful in nanoscale coherent control applications. © 2013 Optical Society of America.We acknowledge support from the European FP7 projects “Nanoantenna” (FP7-HEALTHF5-2009-241818-NANOANTENNA), NMP (NMP3-SL-2011-263104- HINTS), and “SPINTROS” (257654), and the National Projects MAT2009-08398, MAT2009-08494 and FIS2010-19609-C02-C01 from the Spanish Ministerio de Ciencia e Innovacion. We also acknowledge the Marie Curie Actions PIRG06-GA-2009-25647, ITAMOSCINOM, as well as the Basque Government Program PI2011-1 and Etortek-2011 (nanoiker).Peer Reviewe