A5101523792- Molecular Junctions and Nanostructures
- Transition Metal Oxide Nanomaterials
- Surface Chemistry and Catalysis
- Physics of Superconductivity and Magnetism
- Multiferroics and related materials
- Magnetic and transport properties of perovskites and related materials
- Magnetic properties of thin films
- Magnetic Bearings and Levitation Dynamics
- Advanced Condensed Matter Physics
- Metamaterials and Metasurfaces Applications
- Ferroelectric and Piezoelectric Materials
- Surface and Thin Film Phenomena
- Porphyrin and Phthalocyanine Chemistry
- Organic and Molecular Conductors Research
- Plasmonic and Surface Plasmon Research
- Superconducting Materials and Applications
- Photonic and Optical Devices
- Electric Motor Design and Analysis
- Magneto-Optical Properties and Applications
- ZnO doping and properties
- Quantum and electron transport phenomena
- Advanced Chemical Physics Studies
- Advanced Antenna and Metasurface Technologies
- Theoretical and Computational Physics
- Thermal properties of materials
University of California, San Diego
2014-2020
Universidad Autónoma de Madrid
2008-2016
Brookhaven National Laboratory
2016
University of Toronto
2016
Boston College
2016
TU Dresden
2012
Swiss Center for Electronics and Microtechnology (Switzerland)
2011
Material Physics Center
2010
Madrid Institute for Advanced Studies
2008
Instituto de Ciencia de Materiales de Madrid
2008
Nanophotonic resonators offer the ability to design nanoscale optical elements and engineered materials with unconventional properties. Dielectric-based intrinsically support a complete multipolar resonant response low absorption, while metallic provide extreme light confinement enhanced photon–electron interactions. Here, we construct out of prototypical metal–insulator transition material, vanadium dioxide (VO2), demonstrate switching between dielectric plasmonic resonances. We first...
Dielectric-resonator-based nanophotonic devices show promise owing to their low intrinsic losses, support of multipolar resonances, and efficient operation in both reflection transmission configurations. A key challenge is make such dynamically switchable, that optical behavior can be instantaneously reconfigured. In this work we experimentally demonstrate large, broadband, continuous electrical tuning resonances hybrid dielectric–VO2 devices. Our calculations, strong agreement with...
We report on the conformation and self-assembly properties of meso-tetramesitylporphyrin Cu(100). The results show that presence mesityl groups limits interaction between porphyrin ring copper surface, contributing to high mobility at room temperature. At low temperatures it is substrate which determines molecule orientation. intermolecular also very weak, only for coverages do porphyrins self-assemble form large islands with two different mirror symmetric unit cells. can be Fe metalated by...
A near-infrared image sensor with monolithically integrated Ge photodiodes is demonstrated. The technology for the integration of into CMOS process outlined, and measurement results test-diodes full imager are discussed in detail. heterojunction-photodiodes show a quantum efficiency about 30% up to wavelength 1500 nm. tensile strain 0.17% was measured epitaxial layer, which good agreement optically direct bandgap absorption edge 1580 can be operated at room temperature or moderate cooling.
Abstract The realization of a controllable metamagnetic transition from AFM to FM ordering would open the door plethora new spintronics based devices that, rather than reorienting spins in ferromagnet, harness direct control materials intrinsic magnetic ordering. In this study FeRh films with drastically reduced temperatures and large magneto-thermal hysteresis were produced for magnetocaloric applications. Remarkably, giant magnetization changes (measured be as high has ~25%) are realized...
We found atypical pressure dependence in the transport measurements of metal to insulator transition (MIT) epitaxial thin films vanadium sesquioxide (${\mathrm{V}}_{2}{\mathrm{O}}_{3}$). Three different crystallographic orientations and four thicknesses, ranging from 40 500 nm, were examined under hydrostatic pressures $({\mathrm{P}}_{h})$ up 1.5 GPa. All at exhibited a order magnitude resistance change, with temperatures 140 165 K, depending on orientation. This allowed us build...
Abstract Given the paucity of single phase multiferroic materials (with large ferromagnetic moment), composite systems seem an attractive solution to realize magnetoelectric coupling between and ferroelectric order parameters. Despite having antiferromagnetic order, BiFeO 3 (BFO) has nevertheless been a key material due excellent properties at room temperature. We studied superlattice composed 8 repetitions 6 unit cells La 0.7 Sr 0.3 MnO (LSMO) grown on 5 BFO. Significant net uncompensated...
Raman micro-spectroscopy is well suited for studying a variety of properties and has been applied to wide range areas. Combined with tuneable temperature, spectra can offer even more insights into the materials. However, previous designs variable temperature microscopes have made it extremely challenging measure samples low signal levels due thermal positional instabilities as collection efficiencies. Thus contemporary microscope found limited applicability probing subtle physics involved in...
This paper presents a new flexible linear actuator. It is two-phase permanent-magnet tubular motor. An elastomer offers the desired actuator flexibility both between coils of stator and magnets in mover. We determined motor dimensions numerical parameter optimization used various finite element models. The novel artificial muscle designed for tensile loads. electrically powered obtains variable forces. Weights up to 750 g were lifted with minimal bending radius 200 mm. outer diameter direct...
Metasurfaces are two-dimensional nanostructures that allow unprecedented control of light through engineering the amplitude, phase, and polarization across meta-atom resonators. Adding tunability to metasurface components would boost their potential unlock a vast array new application possibilities such as dynamic beam steering, tunable metalenses, reconfigurable meta-holograms, name few. We present here high-index meta-atoms, resonators, metasurfaces reconfigured by thermal effects, near...
Ultra high vacuum scanning tunnelling microscopy revealed chlorosubphthalocyanine to self-organize into discrete well-defined bilayer and trilayer triangular nanocrystallites when evaporated onto a Cu(111) surface.
The adsorption of a TTF derivative (2-[9-(1,3-dithiol-2-ylidene)anthracen-10(9H)-ylidene]-1,3-dithiole, exTTF) on Au(111) has been studied by combination scanning tunneling microscopy, photoelectron spectroscopy, and theoretical calculations. results indicate that the molecule−substrate interaction is dominated S−Au bonds. However, due to conformational reasons, only one two dithiole rings in close contact with surface. As consequence, Au surface much smaller (less than half) Au(111), where...
TCNQ derivatives adsorbed on a metal surface undergo self-limited decyanation reaction that only affects two out of the four cyano groups in molecule. Combined Scanning Tunneling Microscopy/X-ray Photoelectron Spectroscopy experiments and Density Functional Theory calculations relate self-limiting behavior to transfer electrons from
We report on a method to fabricate porous two dimensional (2D) array of porphyrins c(2×2)N∕Cu(001) with pore sizes larger than 5nm, the reported for hydrogen-bonded or coordination organic networks. When deposited square nanopattern created by partial nitridation Cu(001) surface, porphyrin molecules prefer adsorb clean copper instead adsorbing CuN islands, forming 2D array. This nanopatterning technique can be straightforwardly extended other molecular species form walls since its working...
Abstract We report a pressure study of the metamagnetic/ferroelectric hybrid heterostructure quenched FeRh thin film (25 nm) grown on single crystal barium titanate (BTO). It has been previously reported that when BTO undergoes transition massive magnetization and coercivity change is triggered in highly strain sensitive film. Therefore makes for an ideal probe mapping materials structural phase transitions. In this work we demonstrate effect as function both temperature hydrostatic...
We have built long-range ordered, one-dimensional (1D) nanorods by self-assembly of zinc porphyrin derivatives through axial coordination with oxygenated ligands on different noble-metal surfaces. The structures were studied a combination Variable-Temperature Scanning-Tunnelling Microscopy (VT-STM), X-Ray Photoelectron Spectroscopy (XPS) and Density Functional Theory (DFT) calculations. combined morphological, chemical theoretical results demonstrate that the atoms at neighbouring molecules...
Formation of self-assembled chains tetrathiafulvalene (TTF) on the Cu(100) surface has been investigated by scanning tunneling microscopy and density functional theory calculations that include semiempirical van der Waals (vdW) interaction corrections. The show chain structures observed in experiments can only be explained including vdW interactions. molecules are tilted along order to achieve maximal intermolecular interaction. metastable surface, which is consistent with experimental...
We present experimental evidence for (a) multiphase superconductivity and (b) coexistence of magnetism in a single structural phase lithiated iron selenide hydroxide $[(\mathrm{L}{\mathrm{i}}_{1\ensuremath{-}x}\mathrm{F}{\mathrm{e}}_{x})\text{OH]FeSe}$. Magnetic field modulated microwave spectroscopy data confirms with at least two distinct transition temperatures attributed to well-defined superconducting phases ${T}_{\mathrm{SC}1}=40\ifmmode\pm\else\textpm\fi{}2$ K...
This article reports on the temperature-controlled irreversible transition between two isomeric forms of strong electron acceptor dicyano-p-quinonediimine (DCNQI) Cu(100) surface. A combination experiment (time-resolved, variable-temperature scanning tunneling microscopy, STM) and theory (density functional theory, DFT) shows that isomerization barrier is lower than in gas phase or solution due to fact charge transfer from substrate modifies bond configuration molecule, aromatizing quinoid...