A5066662175- Graphene research and applications
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Carbon Nanotubes in Composites
- Advancements in Semiconductor Devices and Circuit Design
- 2D Materials and Applications
- Magnetic properties of thin films
- Molecular Junctions and Nanostructures
- Surface and Thin Film Phenomena
- Thermal properties of materials
- Semiconductor materials and devices
- Nanowire Synthesis and Applications
- Mechanical and Optical Resonators
- Advanced Physical and Chemical Molecular Interactions
- Advanced Memory and Neural Computing
- Magnetic Field Sensors Techniques
- Gas Sensing Nanomaterials and Sensors
- Graphene and Nanomaterials Applications
- Diamond and Carbon-based Materials Research
- Quantum many-body systems
- Atomic and Subatomic Physics Research
- Advanced Thermodynamics and Statistical Mechanics
- Advancements in Battery Materials
- Membrane Separation Technologies
- Surface Chemistry and Catalysis
Institut Català de Nanociència i Nanotecnologia
2016-2025
Consejo Superior de Investigaciones Científicas
2018-2019
Universitat Autònoma de Barcelona
2014-2018
Institució Catalana de Recerca i Estudis Avançats
2017
Technical University of Denmark
2017
Institute of Science and Technology
2016
Barcelona Institute for Science and Technology
2016
Sandia National Laboratories California
2011-2014
Sandia National Laboratories
2012
Arizona State University
2006-2011
We report on fundamental aspects of spin dynamics in heterostructures graphene and transition metal dichalcogenides (TMDCs). By using realistic models derived from first principles we compute the lifetime anisotropy, defined as ratio lifetimes for spins pointing out plane to those plane. find that anisotropy can reach values tens hundreds, which is unprecedented typical 2D systems with spin-orbit coupling indicates a qualitatively new regime relaxation. This behavior mediated by spin-valley...
Graphene has attracted significant interest both for exploring fundamental science and a wide range of technological applications. Chemical vapor deposition (CVD) is currently the only working approach to grow graphene at wafer scale, which required industrial Unfortunately, CVD intrinsically polycrystalline, with pristine grains stitched together by disordered grain boundaries, can be either blessing or curse. On one hand, boundaries are expected degrade electrical mechanical properties...
Large spin-orbital proximity effects have been predicted in graphene interfaced with a transition metal dichalcogenide layer. Whereas clear evidence for an enhanced spin-orbit coupling has found at large carrier densities, the type of and its relaxation mechanism remained unknown. We show first time increased close to charge neutrality point graphene, where topological states are expected appear. Single layer encapsulated between WSe$_2$ hBN is exhibit exceptional quality mobilities as high...
Increasing performance demands on photodetectors and solar cells require the development of entirely new materials technological approaches. We report fabrication optoelectronic characterization a photodetector based optically-thick films dense, aligned, macroscopically long single-wall carbon nanotubes. The exhibits broadband response from visible to mid-infrared under global illumination, with time less than 32 μs. Scanning photocurrent microscopy indicates that signal originates at...
Abstract Engineering 2D material heterostructures by combining the best of different materials in one ultimate unit can offer a plethora opportunities condensed matter physics. Here, van der Waals ferromagnetic insulator Cr 2 Ge Te 6 and graphene, our observations indicate an out-of-plane proximity-induced exchange interaction graphene. The perpendicular magnetic anisotropy results significant modification spin transport precession which be ascribed to interaction. Furthermore, observation...
We report on a theoretical study of the spin Hall Effect (SHE) and weak antilocal-ization (WAL) in graphene/transition metal dichalcogenide (TMDC) heterostructures, computed through efficient real-space quantum transport methods, using realistic tight-binding models parametrized from ab initio calculations. The graphene/WS 2 system is found to maximize proximity effects compared graphene MoS , WSe or MoSe with crucial role played by disorder, given disappearance SHE signals presence strong...
Enhancing the spin-orbit interaction in graphene, via proximity effects with topological insulators, could create a novel 2D system that combines nontrivial spin textures high electron mobility. In order to engineer practical spintronics applications such graphene/topological insulator (Gr/TI) heterostructures, an understanding of hybrid spin-dependent properties is essential. {However date, despite large number experimental studies on Gr/TI heterostructures reporting great variety...
Opto-electronic devices utilizing graphene have already demonstrated unique capabilities, which are much more difficult to realize with conventional technologies. However, the requirements in terms of material quality and uniformity very demanding. A major roadblock towards high-performance nanoscale variations properties, strongly impact macroscopic device behaviour. Here, we present apply opto-electronic nanoscopy measure locally both optical electronic properties devices. This is achieved...
In recent years, predictive computational modeling has become a cornerstone for the study of fundamental electronic, optical, and thermal properties in complex forms condensed matter, including Dirac topological materials. The simulation quantum transport realistic models calls development linear scaling, or order-N, numerical methods, which then enabling tools guiding experimental research supporting interpretation measurements. this review, we describe compare different order-N methods...
Flat bands in moiré systems are exciting new playgrounds for the generation and study of exotic many-body physics phenomena low-dimensional materials. Such is attributed to vanishing kinetic energy strong spatial localization flat-band states. Here, we use numerical simulations examine electronic transport properties such flat magic-angle twisted bilayer graphene presence disorder. We find that while a conventional downscaling mean free path with increasing disorder strength occurs at higher...
In this review we discuss the multifaceted problem of spin transport in hydrogenated graphene from a theoretical perspective. The current experimental findings suggest that hydrogenation can either increase or decrease lifetimes, which calls for clarification. We first spin–orbit coupling induced by local re-hybridization and C–H defect formation together with magnetic moment. First-principles calculations unravel strong interplay exchange couplings. concept scattering resonances, recently...
Grain boundaries, inevitably present in chemical vapor deposited graphene, are expected to have considerable impact on the development of graphene-based hybrid materials with tailored material properties. We demonstrate here critical role polycrystallinity functionalization graphene comparing ozone-induced oxidation remote plasma hydrogenation. show that and hydrogenation occur two consecutive stages upon increasing defect density: an initial step which surface-bound functional groups...
Dirac material–based heterostructures reveal enhanced spin-orbit coupling with an emerging spin texture.
We present a theoretical study of electronic and thermal transport in polycrystalline heterostructures combining graphene (G) hexagonal boron nitride (hBN) grains varying size distribution. By increasing the hBN grain density from few percent to 100%, system evolves good conductor an insulator, with mobility dropping by orders magnitude sheet resistance reaching MΩ regime. The Seebeck coefficient is suppressed above 40% mixing, while conductivity found be on order 30–120 Wm–1 K–1. These...
We theoretically investigate spin dynamics in spin-orbit-coupled materials. In the ballistic limit, lifetime is dictated by dephasing that arises from energy broadening plus a nonuniform precession. For case of clean graphene, we find strong anisotropy with lifetimes can be short even for modest scales, on order few ns. These results offer deeper insight into nature and are also applicable to investigation other systems where spin-orbit coupling plays an important role.
Recent progress in the on-surface synthesis and characterization of nanomaterials is facilitating realization new carbon allotropes, such as nanoporous graphenes, graphynes, 2D π-conjugated polymers. One latest examples biphenylene network (BPN), which was recently fabricated on gold characterized with atomic precision. This gapless organic material presents uncommon metallic conduction, could help develop innovative carbon-based electronics. Here, using first principles calculations quantum...
While graphene-based technology shows great promise for a variety of electronic applications, including radio-frequency devices, the resistance metal-graphene contact is technological bottleneck realization viable graphene electronics. One most important factors in determining junction resistivity. Despite large number experimental works that exist literature measuring resistivity, simple model it still lacking. In this paper, we present comprehensive physical resistivity these junctions,...
We use numerical simulations to predict peculiar magnetotransport fingerprints in polycrystalline graphene, driven by the presence of grain boundaries varying size and orientation. The formation Landau levels is shown be restricted morphology, requiring magnetic length smaller than average radius. nature localization also found unusual, with strongly localized states at center (including usually highly robust zero-energy state) extended electronic lying between levels. These percolate along...
We generalize the diffusive model for spin injection and detection in nonlocal structures to account precession under an applied magnetic field anisotropic medium, which lifetime is not unique depends on orientation. demonstrate that (Hanle) line shape strongly dependent degree of anisotropy orientation field. In particular, we show can be extracted from measured signal, after dephasing oblique field, by using analytical formula with a single fitting parameter. Alternatively, identifying...
The understanding of spin dynamics and relaxation mechanisms in clean graphene the upper time length scales on which devices can operate are prerequisites to realizing spintronic technologies. Here we theoretically reveal nature fundamental different substrates with spin-orbit Rashba fields as low a few tens micron eV. Spin lifetimes ranging from 50 picoseconds up several nanoseconds found be dictated by substrate-induced electron-hole characteristics. A crossover mechanism Dyakonov-Perel...
We report an intriguing transition from the quantum spin Hall phase to effect upon segregation of thallium adatoms adsorbed onto a graphene surface. Landauer-B\"uttiker and Kubo-Greenwood simulations are used access both edge bulk transport physics in disordered thallium-functionalized systems realistic sizes. Our findings not only quantify detrimental effects adatom clustering formation topological state, but also provide evidence for emergence accumulation at opposite sample edges driven...
Conducting materials typically exhibit either diffusive or ballistic charge transport. When electron-electron interactions dominate, a hydrodynamic regime with viscous flow emerges1-13. More stringent conditions eventually yield quantum-critical Dirac-fluid regime, where electronic heat can more efficiently than charge14-22. However, observing and controlling the of in at room temperature has so far remained elusive. Here we observe transport graphene regimes, report controllable transition...