A5074463998- Quantum and electron transport phenomena
- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Graphene research and applications
- Topological Materials and Phenomena
- Multiferroics and related materials
- Iron-based superconductors research
- 2D Materials and Applications
- Magneto-Optical Properties and Applications
- Magnetic Field Sensors Techniques
- Magnetic Properties and Applications
- Advanced Memory and Neural Computing
- Distributed and Parallel Computing Systems
- Quantum Dots Synthesis And Properties
- Theoretical and Computational Physics
- Advanced Chemical Physics Studies
- Magnetism in coordination complexes
- Superconductivity in MgB2 and Alloys
- Molecular Junctions and Nanostructures
- Laser-Matter Interactions and Applications
- Advanced Data Storage Technologies
- Advanced Physical and Chemical Molecular Interactions
- Comparative constitutional jurisprudence studies
- Geophysics and Sensor Technology
Forschungszentrum Jülich
2015-2024
Hospital Braga
2017
Coordenação de Aperfeicoamento de Pessoal de Nível Superior
2012
Ministry of Education
2012
University of California, Irvine
2012
Universidade Federal Fluminense
2010-2011
Universidade do Estado do Rio de Janeiro
2011
The orbital magnetoelectric effect (OME) generically refers to the appearance of an magnetization induced by applied electric field. Here, we show that nanoribbons transition metal dichalcogenides (TMDs) with zigzag (ZZ) edges may exhibit a sizeable OME activated field along ribbons' axis. We examine extracted from monolayer (1L) and bilayer (2L) MoS$_2$ in trigonal (H) structural phase. Transverse profiles angular momentum accumulations are calculated first order longitudinally Our results...
Topological noncollinear magnetic phases of matter are at the heart many proposals for future information nanotechnology, with novel device concepts based on ultrathin films and nanowires. Their operation requires understanding control underlying dynamics, including excitations such as spin waves. So far, no experimental technique has attempted to probe large wave-vector waves in low-dimensional systems. In this paper, we explain how inelastic electron scattering, being suitable...
Abstract Local spins coupled to superconductors give rise several emerging phenomena directly linked the competition between Cooper pair formation and magnetic exchange. These effects are generally scrutinized using a spectroscopic approach which relies on detecting in-gap bound modes arising from breaking, so-called Yu-Shiba-Rusinov (YSR) states. However, impact of local impurities superconducting order parameter remains largely unexplored. Here, we use scanning Josephson spectroscopy...
The growing interest in carbon-based spintronics has stimulated a number of recent theoretical studies on the RKKY interaction graphene, based which energetically favourable alignment between magnetic moments embedded this material can be calculated. general consensus is that strength graphene decays as 1/D3 or faster, where D separation moments. Such an unusually fast decay for 2-dimensional system suggests may too short ranged to experimentally observed graphene. Here we show...
Profiles of the spin and orbital angular momentum accumulations induced by a longitudinally applied electric field are explored in nanoribbons $p$-band systems with honeycomb lattice. We show that zigzag borders can exhibit magnetoelectric effects. More specifically, we have found purely magnetization oriented perpendicularly to ribbon may be these means external field, when sublattice symmetry is broken. The effect rather general occur other multi-orbital materials.
The field of orbitronics has emerged with great potential to impact information technology by enabling environmentally friendly electronic devices. main degree freedom at play is the orbital angular momentum, which can give rise a myriad phenomena such as Hall effect (OHE), torques and magnetoelectric effects. Here, we explore via realistic time-dependent structure simulations magnetic response non-magnetic material, an ultrathin Pt film, ultrafast laser pulses different polarizatons...
Abstract Many-body phenomena are paramount in physics. In condensed matter, their hallmark is considerable on a wide range of material characteristics spanning electronic, magnetic, thermodynamic and transport properties. They potentially imprint non-trivial signatures spectroscopic measurements, such as those assigned to Kondo, excitonic polaronic features, whose emergence depends the involved degrees freedom. Here, we address systematically zero-bias anomalies detected by scanning...
Abstract The ultimate control of magnetic states matter at femtosecond (or even faster) timescales defines one the most pursued paradigm shifts for future information technology. In this context, ultrafast laser pulses developed into extremely valuable stimuli all-optical magnetization reversal in ferrimagnetic and ferromagnetic alloys multilayers, while remains elusive elementary ferromagnets. Here we demonstrate that a single pulse with sub-picosecond duration can lead to bulk nickel,...
Abstract Interfacing magnetism with superconductivity gives rise to a wonderful playground for intertwining key degrees of freedom: Cooper pairs, spin, charge, and spin–orbit interaction, from which emerge wealth exciting phenomena, fundamental in the nascent field superconducting spinorbitronics topological quantum technologies. Magnetic exchange interactions (MEIs), being isotropic or chiral such as Dzyaloshinskii–Moriya interactions, are vital establishing magnetic behavior at these...
Harnessing the spin of single atoms is at heart quantum information nanotechnology based on magnetic concepts. By attaching Co to monatomic Cu chains, we demonstrate ability control orientation by atomic environment. Due spin-orbit coupling (SOC), tilted ≈58° from surface normal toward chain as evidenced inelastic tunneling spectroscopy. These findings are reproduced density functional theory calculations and have implications for pristine Cu(111), which believed be Kondo systems. Our Monte...
Relaxation effects are of primary importance in the description magnetic excitations, leading to a myriad methods addressing phenomenological damping parameters. In this work, we consider several well-established forms calculating intrinsic Gilbert within unified theoretical framework, mapping out their connections and approximations required derive each formula. This scheme enables direct comparison different on same footing consistent evaluation range validity. Most lead very similar...
We demonstrate that ferromagnetic and antiferromagnetic excitations can be triggered by the dynamical spin accumulations induced bulk surface contributions of Hall effect. Due to spin-orbit interaction, a time-dependent density is generated an oscillatory electric field applied parallel atomic planes Fe/W(110) multilayers. For symmetric trilayers Fe/W/Fe in which Fe layers are ferromagnetically coupled, we only collective out-of-phase precession mode excited, while uniform (in-phase) remains...
We demonstrate with a fully quantum-mechanical approach that graphene can function as gate-controllable transistors for pumped spin currents, i.e., stream of angular momentum induced by the precession adjacent magnetizations, which exists in absence net charge currents. Furthermore, we propose proof concept how these currents be modulated an electrostatic gate. Because our proposal involves nano-sized systems very high speeds and any applied bias, it is potentially useful development capable...
Abstract Spin-orbit-related effects offer a highly promising route for reading and writing information in magnetic units of future devices. These phenomena rely not only on the static magnetization orientation but also its dynamics to achieve fast switchings that can reach THz range. In this work, we consider Co/Pt Fe/W bilayers show accounting phase difference between different processes is crucial correct description dynamical currents. By tuning each system towards ferromagnetic...
The ability to realistically simulate the electronic structure of superconducting materials is important understand and predict various properties emerging in both topological spintronics realms. We introduce a tight-binding implementation Bogoliubov–de Gennes method, parameterized from density functional theory, which we utilize explore bulk thin films Nb, known host significant gap. latter useful for applications such as exploration trivial in-gap states. Here, focus on simulation’s...
We demonstrate with a quantum-mechanical approach that carbon nanotubes are excellent spin-current waveguides and able to carry information stored in precessing magnetic moment for long distances very little dispersion tunable degrees of attenuation. Pulsed excitations predicted travel the nanotube Fermi velocity induce similar remote locations. Such an efficient way transporting suggests promising candidates memory devices fast magnetization switchings.
Abstract Nuclear spins are among the potential candidates prospected for quantum information technology. A recent breakthrough enabled to atomically resolve their interaction with electron spin, so-called hyperfine interaction, within individual atoms utilizing scanning tunneling microscopy (STM). Intriguingly, this was only realized a few species put on two-layers thick MgO. Here, we systematically quantify from first-principles interactions of whole series 3d transition adatoms deposited...
Abstract Terahertz spintronics offers the prospect of devices which are both faster and more energy-efficient. A promising route to achieve this goal is exploit current-induced spin-orbit torques. However, high-frequency properties these quantities remain unexplored experimentally theoretically, within a realistic material-specific approach. Here we investigate dynamical transverse components torques uncover contributions longitudinal magnetic moment capable changing its magnitude. We show...
Quantum fluctuations are ubiquitous in physics. Ranging from conventional examples like the harmonic oscillator to intricate theories on origin of universe, they alter virtually all aspects matter, including superconductivity, phase transitions, and nanoscale processes. As a rule thumb, smaller object, larger its impact. This poses serious challenge modern nanotechnology, which aims at total control via atom-by-atom engineered devices. In magnetic nanostructures, high stability signal is...
In ultrathin ferromagnets deposited on metallic substrates, excitation of precessional motion the spins produces a spin current in substrate that transports angular momentum out film. This phenomenon is referred to as pumping, and source damping motion. Spin pumping enters importantly description dynamics other nanoscale subnanoscale systems well. this paper, we present an approach based Kubo formalism allows explicit calculation its spatial variation. We use explore features generated by...
We investigate the dynamics of Fe adatoms and dimers deposited on Cu(111) metallic surface in presence spin-orbit coupling, within time-dependent density functional theory. The \textit{ab initio} results provide material-dependent parameters that can be used semiclassical approaches, which are for insightful interpretations excitation modes. By manipulating surroundings magnetic elements, we show elliptical precessional motion may induced through modification anisotropy energy. also...
Graphene has been identified as a promising material with numerous applications, particularly in spintronics. In this paper we investigate the peculiar features of spin excitations magnetic units deposited on graphene nanoribbons and how they can couple through dynamical interaction mediated by currents. We examine detail lifetimes identify pattern caused vanishing density states sites pristine ribbons armchair borders. Impurities located these become practically invisible to but be made...
We investigate the induced orbital magnetization density in a Rashba electron gas with magnetic impurities. Relying on classical electrodynamics, we obtain this quantity through bound currents composed of paramagnetic and diamagnetic-like contribution which emerge from spin-orbit interaction. Similar to Friedel charge ripples, oscillate as function distance away impurity characteristic wavelengths defined by Fermi energy strength The net was found be order magnitude its spin counterpart....