A5016260959- Molecular Junctions and Nanostructures
- Superconductivity in MgB2 and Alloys
- ZnO doping and properties
- Physics of Superconductivity and Magnetism
- Surface and Thin Film Phenomena
- Iron-based superconductors research
- Quantum Dots Synthesis And Properties
- Advanced Chemical Physics Studies
- Copper-based nanomaterials and applications
- Semiconductor materials and devices
- Surface Chemistry and Catalysis
- Quantum and electron transport phenomena
- X-ray Diffraction in Crystallography
- Gold and Silver Nanoparticles Synthesis and Applications
- Electronic and Structural Properties of Oxides
- Chalcogenide Semiconductor Thin Films
- Magnetism in coordination complexes
- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- DNA and Nucleic Acid Chemistry
- Crystallization and Solubility Studies
- Conducting polymers and applications
- Machine Learning in Materials Science
- Photochemistry and Electron Transfer Studies
- Phase-change materials and chalcogenides
Istituto Nanoscienze
2016-2025
Duke University
2016-2024
Università degli Studi eCampus
2022-2023
University of North Texas
2013-2020
Azienda Unita' Sanitaria Locale Di Modena
2017-2020
University of Modena and Reggio Emilia
2001-2017
Istituto di Scienza e Tecnologie dell'Informazione "Alessandro Faedo"
2016
Institute for the Chemistry of OrganoMetallic Compounds
2016
Scuola Internazionale Superiore di Studi Avanzati
2011-2015
Norfolk State University
2013
The need for improved functionalities in extreme environments is fuelling interest high-entropy ceramics
We present a comprehensive first-principles study of the ballistic transport properties low dimensional nanostructures such as linear chains atoms (Al, C) and carbon nanotubes in presence defects. A novel approach is introduced where quantum conductance computed from combination accurate plane-wave electronic structure calculations, evaluation corresponding maximally-localized Wannier functions, calculation by real-space Green's function method based on Landauer formalism. This...
Ab initio calculations of the spontaneous polarization and piezoelectric properties boron nitride nanotubes show that they are excellent systems with response values larger than those polymers. The intrinsic chiral symmetry induces an exact cancellation total in ideal, isolated arbitrary indices. Breaking this by intertube interaction or elastic deformations comparable to wurtzite semiconductors.
Although generally ascribed to the presence of defects, an ultimate assignment different contributions emission spectrum in terms surface states and deep levels ZnO nanostructures is still lacking. In this work we unambiguously give first evidence that zinc vacancies at (1010) nonpolar surfaces are responsible for green luminescence nanostructures. The result obtained by performing exhaustive comparison between spatially resolved cathodoluminescence spectroscopy imaging ab initio...
Using first principles calculations based on density functional theory and a coupled finite-fields/finite-differences approach, we study the dielectric properties, phonon dispersions Raman spectra of ZnO, material whose internal polarization fields require special treatment to correctly reproduce ground state electronic structure coupling with external fields. Our results are in excellent agreement existing experimental measurements provide an essential reference for characterization...
Abstract We revise the electronic and optical properties of ZnS on basis first principles simulations, in view novel routes for optoelectronic photonic devices, such as transparent conductors plasmonic applications. In particular, we consider doping effects, induced by Al Cu. It is shown that with imparts a n-character allows activity mid-IR can be exploited IR metamaterials, while Cu induces spin dependent p-type character to host, opening way engineering p-n junctions, conductive materials...
A promising trend in plasmonics involves shrinking the size of plasmon-supporting structures down to a few nanometers, thus enabling control over light–matter interaction at extreme-subwavelength scales. In this limit, quantum mechanical effects, such as nonlocal screening and quantization, strongly affect plasmonic response, rendering it substantially different from classical predictions. For very small clusters molecules, collective modes are hard distinguish other excitations...
By combining first-principles theoretical calculations and experimental optical structural characterization such as spectroscopic ellipsometry, X-ray spectroscopy, electron microscopy, we study the dielectric permittivity plasmonic properties of ultrathin TiN films at an atomistic level. Our results indicate a remarkably persistent metallic character progressive red shift plasmon energy thickness film is reduced, which consistent with previous studies. The microscopic origin this trend...
Triplet ground-state organic molecules are of interest with respect to several emerging technologies but usually show limited stability, especially as thin films. We report an diradical, consisting two Blatter radicals, that possesses a triplet ground state singlet-triplet energy gap, ΔEST ≈ 0.4-0.5 kcal mol-1 (2J/k 220-275 K). The diradical robust thermal onset decomposition above 264 °C (TGA). In toluene/chloroform, glassy matrix, and fluid solution, equilibrium between conformations 0.4...
Discovering multifunctional materials with tunable plasmonic properties, capable of surviving harsh environments is critical for advanced optical and telecommunication applications. We chose high-entropy transition-metal carbides because their exceptional thermal, chemical stability, mechanical properties. By integrating computational thermodynamic disorder modeling time-dependent density functional theory characterization, we discovered a crossover energy in the infrared visible range,...
By combining experimental and theoretical approaches, we study the adsorption of pentacene on copper as a model for coupling between aromatic molecules metal surfaces. Our results interface electronic structure are not compatible with purely physisorption picture, which is conventionally employed such systems. Nay, demonstrate mixing molecular orbitals states.
Molecular sensitization of the single-crystal ZnO (101̅0) surface through absorption catechol chromophore is investigated by means density functional approaches. The resulting type II staggered interface recovered in agreement with experiments, and its origin traced back to presence molecular-related states gap metal−oxide electronic structure. A systematic analysis carried out for further catecholate adsorbates allows us identify basic mechanisms that dictate energy position states....
Using model interaction Hamiltonians for both electrons and phonons Green's function formalism ballistic transport, we have studied the thermal conductance thermoelectric properties of graphene nanoribbons (GNR), GNR junctions periodic superlattices. Among our findings established role that interfaces play in determining response systems across single In general, increasing number a system increases peak ZT values are thus maximized superlattice. Moreover, proved behavior is largely...
Using first-principles calculations, we investigate the origin of near-infrared plasmonic activity in Al:ZnO transparent conducting oxides. Our results predict realistic values for plasma frequency and free electron density as a function Al doping agreement with recent experimental results. We also provide microscopic insight on formation surface-plasmon polaritons at Al:ZnO/ZnO interfaces terms characteristic lengths that can be measured by experiments. The direct comparison standard metals...
Scanning tunneling microscopy and local conductance mapping show spin-state coexistence in bilayer films of Fe[(H2Bpz2)2bpy] on Au(111) that is independent temperature between 131 300 K. This modification bulk behavior attributed part to the unique packing constraints film promote deviations from behavior. The density states measured for different spin shows high-spin molecules have a smaller transport gap than low-spin are agreement with functional theory calculations.
We present a straightforward, noniterative projection scheme that can represent the electronic ground state of periodic system on finite atomic-orbital-like basis, up to predictable number states and with controllable accuracy. By co-filtering projections plane-wave Bloch high-kinetic-energy components, richness space thus exactly-reproduced bands be selectively increased at negligible computational cost, an essential requirement for design efficient algorithms structure simulations...
The development of plasmonic and metamaterial devices requires the research high-performance materials alternative to standard noble metals. Renewed as a refractory stable compound for durable coatings, titanium nitride has recently been proposed an efficient material. Here, by using first-principles approach, we investigate plasmon dispersion relations TiN bulk predict effect pressure on its optoelectronic properties. Our results explain main features in visible range prove universal...
The growth of films [H2B(pz)2]Fe(II)(bpy) on Au(111) is characterized from the bilayer film to multilayer regime. Scanning tunneling microscopy shows a transition well-ordered, uniform poorly-ordered at larger thicknesses. Previous local spectroscopy and conductance mapping in permit identification coexisting molecular spin-states all temperatures. New ultraviolet photoelectron consistent with this picture agreement density states calculated by functional theory. In thicker polycrystalline...
The spin and orbital configuration of magnetic metal phthalocyanines (MPcs) deposited on metallic substrates are strongly influenced by the rehybridization molecular states with underlying metal. FePc, CoPc, CuPc isolated molecules archetypal systems to investigate interrelationship between moments symmetry after deposition a substrate. MPcs form long-range ordered chains self-assembled along reconstructed channels Au(110) surface. X-ray circular dichroism from ${L}_{2,3}$ absorption edges...
We apply a recently developed time-dependent density functional theory (TDDFT) algorithm based on the complex dynamical polarizability to calculate photoabsorption spectrum of following series closed-shell icosahedral clusters increasing size (namely, [M13]5+, [M55]3–, [M147]−, and [M309]3+ with M = Ag, Au), focusing in particular their plasmonic response. The new method is shown be computationally very efficient: it simultaneously retains information excited-state wave function provides...
The microscopic definition of plasmons in nanosystems is a tremendous challenge. Any sharp distinction the excitation nature (nonplasmonic vs plasmonic) becomes blurred at nanoscale, where quantum effects become important. Here we introduce concept plasmonicity index, i.e., direct measure plasmonic character optical excitations nanosystems. Its based on rigorous theoretical derivation, which leads to physically sound result that index related capability enhancing locally an applied...