A5029197029- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- Quantum and electron transport phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Photonic and Optical Devices
- Strong Light-Matter Interactions
- Advanced Fiber Laser Technologies
- Mechanical and Optical Resonators
- Gold and Silver Nanoparticles Synthesis and Applications
- Carbon Nanotubes in Composites
- Quantum Information and Cryptography
- Thermal Radiation and Cooling Technologies
- Quantum many-body systems
- Quantum chaos and dynamical systems
- Topological Materials and Phenomena
- Metamaterials and Metasurfaces Applications
- Quantum optics and atomic interactions
- Advanced Thermoelectric Materials and Devices
- Quantum, superfluid, helium dynamics
- Theoretical and Computational Physics
- Surface and Thin Film Phenomena
- Photonic Crystals and Applications
- Nanowire Synthesis and Applications
- Photorefractive and Nonlinear Optics
- Quantum Mechanics and Applications
University of Pisa
2019-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2024
Italian Institute of Technology
2017-2019
Lancaster University
2019
University of Genoa
2018
Scuola Normale Superiore
2006-2017
Istituto Nanoscienze
2010-2017
National Enterprise for NanoScience and NanoTechnology
2010-2016
Austrian Academy of Sciences
2010-2013
Istituto Nazionale per la Fisica della Materia
2010
Graphene hosts a unique electron system in which electron-phonon scattering is extremely weak but electron-electron collisions are sufficiently frequent to provide local equilibrium above the temperature of liquid nitrogen. Under these conditions, electrons can behave as viscous and exhibit hydrodynamic phenomena similar classical liquids. Here we report strong evidence for this transport regime. We found that doped graphene exhibits an anomalous (negative) voltage drop near...
We discuss an open driven-dissipative many-body system, in which the competition of unitary Hamiltonian and dissipative Liouvillian dynamics leads to a nonequilibrium phase transition. It shares features quantum transition that it is interaction driven, classical transition, ordered continuously connected thermal state. characterize diagram critical behavior at approached as function time. find novel fluctuation induced dynamical instability, occurs long wavelength consequence subtle...
Motivated by recent experimental progress in preparing encapsulated graphene sheets with ultra-high mobilities up to room temperature, we present a theoretical study of dc transport doped the hydrodynamic regime. By using continuity and Navier-Stokes equations, demonstrate analytically that measurements non-local resistances multi-terminal Hall bar devices can be used extract shear viscosity two-dimensional (2D) electron liquid graphene. We also discuss how probe viscosity-dominated regime...
A novel liquid-phase exfoliation of layered crystals enables the production defect-free and high quality 2D-crystal dispersions on a large scale.
We present a combined analytical and numerical study of the early stages (sub-100-fs) nonequilibrium dynamics photoexcited electrons in graphene. employ semiclassical Boltzmann equation with collision integral that includes contributions from electron-electron (e-e) electron--optical phonon interactions. Taking advantage circular symmetry employing massless Dirac fermion (MDF) Hamiltonian, we are able to perform an essentially e-e contribution integral. This allows us take particular care...
We present a micrometer scale, on-chip integrated, plasmonic enhanced graphene photodetector (GPD) for telecom wavelengths operating at zero dark current. The GPD is designed and optimized to directly generate photovoltage has an external responsivity~12.2V/W with 3dB bandwidth~42GHz. utilize Au split-gates a$\sim$100nm gap electrostatically create p-n-junction simultaneously guide surface plasmon polariton gap-mode. This increases light-graphene interaction optical absorption results in...
For many of the envisioned optoelectronic applications graphene it is crucial to understand sub-picosecond carrier dynamics immediately following photoexcitation, as well effect on electrical conductivity - photoconductivity. Whereas these topics have been studied using various ultrafast experiments and theoretical approaches, controversial incomplete explanations put forward concerning sign photoconductivity, occurrence significance creation additional electron-hole pairs, and, in...
It is widely believed that carrier-density inhomogeneities ("electron-hole puddles") in single-layer graphene on a substrate like quartz are due to charged impurities located close the sheet. Here we demonstrate by using Kohn-Sham-Dirac density-functional scheme corrugations real sample sufficient determine electron-hole puddles length scales larger than spatial resolution of state-of-the-art scanning tunneling microscopy.
Recent progress in the design and fabrication of artificial two-dimensional (2D) materials paves way for experimental realization electron systems moving on complex geometries, such as plane fractals. In this work, we calculate quantum conductance a 2D gas roaming Sierpinski carpet (SC), i.e., fractal with Hausdorff dimension intermediate between 1 2. We find that fluctuations are function energy graph, whose can be chosen by changing geometry SC. This behavior is independent underlying...
Coupled quantum electrodynamics (QED) cavities have been recently proposed as new systems to simulate a variety of equilibrium and non-equilibrium many-body phenomena. We present brief review their main properties together with survey the last developments field some perspectives concerning experimental realizations possible theoretical directions.
We analyze the nonequilibrium dynamics of a gas interacting photons in an array coupled dissipative nonlinear cavities when driven by pulsed external coherent field. Using mean-field approach, we show that response system is strongly sensitive to underlying (equilibrium) quantum phase transition from Mott insulator superfluid state at commensurate filling. find coherence cavity emission after quench can be used determine diagram optical many-body even presence dissipation.
We outline a Kohn-Sham-Dirac density functional theory (DFT) scheme for graphene sheets that treats slowly varying inhomogeneous external potentials and electron-electron interactions on equal footing. The is able to account the unusual property exchange-correlation contribution chemical potential increases with carrier in graphene. consequences of this advantages disadvantages using DFT approach describe it are discussed. illustrated by solving equations self-consistently model random...
The photoresponse of graphene has recently received considerable attention. main mechanisms yielding a finite dc response to an oscillating radiation field which have been investigated include responses photovoltaic, photothermoelectric, and bolometric origin. In this article, we present fully analytical theory mechanism is based on the excitation plasma waves in gated sheet. By employing relativistic hydrodynamics, demonstrate that plasma-wave photodetection substantially influenced by...
We study the nonequilibrium dynamics of a many-body bosonic system on lattice, subject to driving and dissipation. The time evolution is described by master equation, which we treat within generalized Gutzwiller mean field approximation for density matrices. dissipative processes are engineered such that system, in absence interaction between bosons, driven into homogeneous steady state with off-diagonal long-range order. investigate how coherent affects properties qualitatively derive phase...
Single-layer graphene sheets are typically characterized by long-wavelength corrugations (ripples) which can be shown to at the origin of rather strong potentials with both scalar and vector components. We present an extensive microscopic study, based on a self-consistent Kohn-Sham-Dirac density-functional method, carrier density distribution in presence these ripple-induced external fields. find that spatial fluctuations essentially controlled component, especially nearly-neutral sheets,...
We study the driven-dissipative dynamics of photons interacting with an array micromechanical membranes in optical cavity. Periodic membrane driving and phonon creation result effective photon-number conserving non-unitary dynamics, which features a steady state long-range photonic coherence. If leakage out cavity is counteracted by incoherent modes, we show that system undergoes dynamical phase transition to A minimal system, composed two cavity, studied detail, it shown be realistic setup...
The shear viscosity of a variety strongly interacting quantum fluids, ranging from ultracold atomic Fermi gases to quark-gluon plasmas, can be accurately measured. On the contrary, no experimental data exist, best our knowledge, on two-dimensional electron liquids hosted in solid-state matrix. In this Letter we propose Corbino disk device, which allows determination liquid dc potential difference that arises between inner and outer edge response an oscillating magnetic flux.
CMOS-compatible materials for efficient energy harvesters at temperatures characteristic on-chip operation and body temperature are the key ingredients sustainable green computing ultralow power Internet of Things applications. In this context, lattice thermal conductivity (κ) new group IV semiconductors, namely Ge1–xSnx alloys, investigated. Layers featuring Sn contents up to 14 at.% epitaxially grown by state-of-the-art chemical-vapor deposition on Ge buffered Si wafers. An abrupt decrease...
We study photon condensation phenomena in a driven and dissipative array of superconducting microwave resonators. Specifically, we show that by using an appropriately designed coupling photons to qubits, effective mechanism can be engineered, which scatters towards low-momentum states while conserving their number. This mimics tunable bosons low-temperature bath, leads the formation stationary condensate presence losses under continuous-driving conditions. In this paper, propose realistic...
The ability to tune the optical response of a material via electrostatic gating is crucial for optoelectronic applications, such as electro-optic modulators, saturable absorbers, limiters, photodetectors, and transparent electrodes. band structure single layer graphene (SLG), with zero-gap, linearly dispersive conduction valence bands, enables an easy control Fermi energy, EF, threshold interband absorption. Here, we report tunability SLG nonequilibrium in near-infrared (1000–1700...
Deterministic fractal antennas are employed to realize multimodal plasmonic devices. Such structures show strongly enhanced localized electromagnetic fields typically in the infrared range with a hierarchical spatial distribution. Realization of engineered operating optical regime would enable nanoplasmonic platforms for applications, such as energy harvesting, light sensing, and bio/chemical detection. Here, we introduce novel multiband metamaterial based on Sierpinski carpet (SC)...
Hot electrons dominate the ultrafast (∼fs–ps) optical and electronic properties of metals semiconductors, they are exploited in a variety applications including photovoltaics photodetection. We perform power-dependent third-harmonic generation measurements on gated single-layer graphene detect significant deviation from cubic power law expected for process. assign this to presence hot electrons. Our results indicate that performance nonlinear photonics devices based graphene, such as...
Recent advances in nanofabrication methods have made it possible to create complex two-dimensional artificial structures, such as fractals, where electrons can be confined. The optoelectronic and plasmonic properties of these exotic quantum electron systems are largely unexplored. In this paper, we calculate the optical conductivity a gas Sierpinski carpet (SC). SC is paradigmatic fractal that fabricated planar solid-state matrix by means an iterative procedure. We show function frequency...