A5106790572- Molecular Junctions and Nanostructures
- Quantum and electron transport phenomena
- Graphene research and applications
- Physics of Superconductivity and Magnetism
- Advanced Chemical Physics Studies
- Magnetic properties of thin films
- Surface and Thin Film Phenomena
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Force Microscopy Techniques and Applications
- Surface Chemistry and Catalysis
- Magnetism in coordination complexes
- 2D Materials and Applications
- Carbon Nanotubes in Composites
- Machine Learning in Materials Science
- Spectroscopy and Quantum Chemical Studies
- Multiferroics and related materials
- Electrochemical Analysis and Applications
- Magnetic Properties and Applications
- Superconducting Materials and Applications
- Fullerene Chemistry and Applications
- Advanced Physical and Chemical Molecular Interactions
- Topological Materials and Phenomena
- Traffic Prediction and Management Techniques
- Semiconductor materials and devices
Universidad de Oviedo
2016-2025
Nanomaterials and Nanotechnology Research Center
2015-2025
Lancaster University
2011-2014
University of Duisburg-Essen
2010
Consejo Superior de Investigaciones Científicas
2009
Universitat Politècnica de Catalunya
2002
Central University Hospital of Asturias
2001
Los Alamos National Laboratory
1994-1995
Universidad Autónoma de Madrid
1870-1994
Rutgers, The State University of New Jersey
1992-1993
Ab initio computational methods for electronic transport in nanoscaled systems are an invaluable tool the design of quantum devices. We have developed a flexible and efficient algorithm evaluating $I\text{\ensuremath{-}}V$ characteristics atomic junctions, which integrates nonequilibrium Green's function method with density functional theory. This is currently implemented package SMEAGOL. The heart SMEAGOL our scheme constructing surface functions describing current-voltage probes. It...
A review of the present status, recent enhancements, and applicability SIESTA program is presented. Since its debut in mid-nineties, SIESTA's flexibility, efficiency free distribution has given advanced materials simulation capabilities to many groups worldwide. The core methodological scheme combines finite-support pseudo-atomic orbitals as basis sets, norm-conserving pseudopotentials, a real-space grid for representation charge density potentials computation their associated matrix...
We have developed an efficient simulation tool 'GOLLUM' for the computation of electrical, spin and thermal transport characteristics complex nanostructures. The new multi-scale, multi-terminal addresses a number challenges functionalities that emerged in nanoscale-scale over past few years. To illustrate flexibility functionality GOLLUM, we present range demonstrator calculations encompassing charge, transport, corrections to density functional theory such as LDA+U spectral adjustments,...
Abstract Twisting 2D van der Waals magnets allows the formation and control of different spin‐textures, as skyrmions or magnetic domains. Beyond rotation angle, spin reversal processes can be engineered by increasing number layers forming twisted heterostructure. Here, pristine monolayers bilayers A‐type antiferromagnet CrSBr are considered building blocks. By rotating 90 degrees these units, symmetric (monolayer/monolayer bilayer/bilayer) asymmetric (monolayer/bilayer) heterostructures...
This review explains the relationship between density functional theory and strongly correlated models using simplest possible example, two-site Hubbard model. The to traditional quantum chemistry is included. Even in this elementary where exact ground-state energy site occupations can be found analytically, there much explained terms of underlying logic aims theory. Although usual solution analytic, given only implicitly. We overcome difficulty Levy-Lieb construction create a...
GeSe and SnSe monochalcogenide monolayers bilayers undergo a two-dimensional phase transition from rectangular unit cell to square at temperature $T_c$ well below the melting point. Its consequences on material properties are studied within framework of Car-Parrinello molecular dynamics density-functional theory. No in-gap states develop as structural takes place, so that these phase-change materials remain semiconducting above $T_c$. As in-plane lattice transforms rectangle onto $T_c$,...
A theoretical analysis of the contact resistance in scanning tunneling microscope at very small distances is presented. For a single atom, we find that saturates close contact, its value being $\frac{h}{{2e}^{2}}$. Our recent experimental results Gimzewski and M\"oller shows mechanical instability predicted by Pethica co-workers appears for distance 1.5 \AA{} between tip sample.
We have been kindly informed of some minor errors in the above paper. (1) On page 8003 equation (15) is not correct. The correct formulae (and ones actually programmed) are shown pdf file. Since were employed program, all results This mistake was pointed out by Hyungjun Lee from Yonsei University (Korea). (2) 8000, at end first paragraph it states 'A hybrid option to use frozen core methods, such as PAW[10] and FPLO[11], which will be discussed here.' where should say, methods FPLO [11], here.'.
In realizing practical non-trivial topological electronic phases stable structures need to be determined first. Tin and lead do stabilize an optimal two-dimensional high-buckled phase --a hexagonal-close packed bilayer structure with nine-fold atomic coordination-- they not fullerenes, as demonstrated by energetics, phonon dispersion curves, the structural optimization of finite-size samples. The are metallic due their high coordination. fluorinated tin lacks three-fold symmetry it...
The conductance and the decay of as a function molecular length within homologous series oligoynes, Me3Si—(C≡C)n—SiMe3 (n = 2, 3, 4, or 5), is shown to depend strongly on solvent medium. Single molecule junction measurements have been made with I(s) method for each member 5) in mesitylene (MES), 1,2,4-trichlorobenzene (TCB), propylene carbonate (PC). In mesitylene, lower obtained across whole higher (β ≈ 1 nm–1). contrast, give values 0.1 0.5 nm–1 respectively). This behavior rationalized...
Pseudopotential-based Density-Functional Theory (DFT) permits the calculation of material properties with a modest computational effort, besides an acknowledged tradeoff generating and testing pseudopotentials that reproduce established benchmark structural electronic properties. To facilitate needed benchmarking process, here we present pragmatic method to optimize for arbitrary materials directly from eigenvalue sets consistent all-electron results. This thus represents much route creation...
Using first principles simulations we perform a detailed study of the structural, electronic, and transport properties monatomic platinum chains, sandwiched between electrodes. First, demonstrate that most stable atomic configuration corresponds to zigzag arrangement gradually straightens as chains are stretched. Second, find averaged conductance shows slight parity oscillations with number atoms in chain. Additionally, fixed oscillates end pulled apart, due gradual closing opening channels...
We examine electron transport through a single-molecule magnet ${\mathrm{Mn}}_{12}$ bridged between Au electrodes using the first-principles method. find crucial features which were inaccessible in model Hamiltonian studies: spin filtering and strong dependence of charge distribution on local environments. The remains robust with different molecular geometries interfaces, correlations, while over strongly depends them. point out qualitative difference locally charged free-electron-charged...
We analyze the impact of magnetic anisotropy on geometric structure and ordering small atomic clusters palladium, iridium, platinum, gold. have employed a noncollinear implementation density functional theory where spin-orbit interaction has been included self-consistently. The size ranges from two to five, six, or seven atoms, depending element. Our results highlight relevance in properties made fourth- fifth-row elements.
We have undertaken theoretical studies of spin and orbital magnetic moments as well anisotropy energies for ${M}_{13}$ $(M=\text{Fe},\text{Co},\text{Ni})$ ${M}_{13}{\text{Pt}}_{n}$ $(n=3,4,5,20)$ clusters including the spin-orbit coupling in framework density functional theory. For all considered we find tendencies small structural distortions which can be characterized by either Jahn-Teller (JT) or Mackay transformations (MT). The energy (MAE) along with are calculated icosahedral...
To demonstrate the potential of nanopores in bilayer graphene for DNA sequencing, we computed current-voltage characteristics a junction containing nanopore and found that they change significantly when nucleobases are transported through pore. sensitivity selectivity example devices, probability distribution PX(β) quantity β representing logarithmic current pore due to presence nucleobase X (X = adenine, thymine, guanine, or cytosine). We quantified bilayer-graphene by showing exhibits...
The precise determination of dose-effect curves and the combination effect drugs is crucial importance in development new therapies for most dreadful diseases. We have found that current implementations theory Chou et al. are not accurate enough some circumstances might lead to erroneous predictions synergistic or antagonistic behaviour. identified source inaccuracies fixed it thereby improving accuracy those methods. Here we explain main features our approach demonstrate its higher as...
We analyze a new family of carbon nanotube-based molecular wires, formed by encapsulating metallocene molecules inside the nanotubes. Our simulations, which are based on combination nonequilibrium Green function techniques and density functional theory, indicate that these wires can be engineered to exhibit desirable magnetotransport effects for use in spintronics devices. The proposed structures should also resilient room-temperature fluctuations, expected have high yield.
Abstract We demonstrate the bottom-up in-situ formation of organometallic oligomer chains at single-molecule level. The are formed using mechanically controllable break junction technique operated in a liquid environment, and consist alternating isocyano-terminated benzene monomers coordinated to gold atoms. show that chaining process is critically determined by surface density molecules. In particular, we reducing local supply molecules within junction, either lowering molecular...
Two-dimensional (2D) materials that exhibit spontaneous magnetization, polarization, or strain (referred to as ferroics) have the potential revolutionize nanotechnology by enhancing multifunctionality of nanoscale devices. However, multiferroic order is difficult achieve, requiring complicated coupling between electron and spin degrees freedom. We propose a universal method engineer multiferroics from van der Waals magnets taking advantage fact changing stacking 2D layers can break inversion...
Abstract: The VanGO Alaminos to Dagupan Van scheduling, queuing, and booking system for convenience commuters addresses the challenges faced by van drivers, dispatchers, along route, focusing on enhancing transportation efficiency improving overall travel experience. Using Rapid Application Development (RAD) methodology, this study aims design develop a strong that integrates key features such as real-time updates locations, efficient route optimization, reliable scheduling algorithms....
The crossover between ideal Josephson behavior and uniform superconducting flow is studied by solving exactly the Ginzburg-Landau equation for a one-dimensional superconductor in presence of an effective \ensuremath{\delta}-function potential arbitrary strength. As scattering turned off, pairs solutions with equal current evolve into solitonic solution nonzero phase offset. It also argued that microscopic description must satisfy self-consistency condition, which shown to guarantee...
The existence of a spin-disordered ground state for the frustrated ${\mathit{J}}_{1\mathrm{\ensuremath{-}}}$${\mathit{J}}_{2\mathrm{\ensuremath{-}}}$${\mathit{J}}_{3}$ quantum Heisenberg antiferromagnet on square lattice is reconsidered. It argued that there unique action continuous through whole phase diagram, except at Lifshitz point, so N\'eel and helicoidal states cannot coexist has to be an intermediate spin-liquid state. To show it, detailed study combining spin-wave theory,...