arXiv subjects

Marcel Di Vece

Publications and source records attributed to Marcel Di Vece.

4 recordsLinked to original sources

arXiv2026

Magnetron Sputtering Formation of Nanoparticles from Natural Olivine Rock for Atmospheric CO2 Capture

The two-birds-one-stone mineralization of CO2 by olivine, is a promising method to both capture carbon directly from the atmosphere and at the same time locking it for storage or utilization. Converting olivine to the nanoscale considerably enhances the kinetics without the need for high temperatures or pressures. Here we present the fabrication of olivine nanoparticles from a natural rock that were fabricated in a gas aggregation magnetron nanoparticle generator. The nanoparticle yield was optimized by enhancing the argon plasma sputter plasma by hydrogen introduction and varying the aggregation distance. The hysteresis of the argon sputter plasma with respect to power is a promising property towards energy efficiency. The formation of well-defined olivine nanoparticles and their subsequent absorption of atmospheric CO2 was confirmed by a suite of techniques. The olivine sputter target surface revealed an intricate interplay between the sputter plasma and olivine composition in terms of crystallinity and morphology. More broadly, this work forms the next step in the practical application of Olivine nanoparticles for economical carbon capture and storage, it also is the starting point for the use of this specific nanoparticle technology for mineral-to-nanoparticle conversion.

physics.gen-ph↗

arXiv2026

Thermal rectification due to phonon confinement in nanoparticles

We demonstrate that thermal rectification can arise at the contact between two spherical nanoparticles of identical material but different size due to the geometric confinement of phonons. This confinement suppresses long-wavelength phonons differently in differently sized particles and creates a size-dependent gap in the phonon density of states. This gives rise to direction-dependent heat transport even in perfectly homogeneous materials. We develop an analytical model based on phonon confinement and phonon ray-tracing in the Casimir regime and derive expressions for heat fluxes and rectification efficiency as functions of particle sizes and temperatures. The model predicts measurable rectification efficiencies for nanoparticles with radii of a few tens of nanometers, reaching fraction of percent at room temperature and much larger values at low temperatures. The proposed mechanism provides a straightforward and scalable route to thermal rectification in granular nanomaterials without requiring material heterogeneity or strong nonlinearities.

cond-mat.mes-hall↗

arXiv2026

Thermal Rectification from Size-Dependent Phonon Confinement in Nanoparticle Assemblies

Thermal insulation remains an important technological challenge across the vast number of applications, from living quarters to quantum technology. Here, we exploit the size-dependent modification of the phonon density of states arising from phonon confinement in nanoparticles to fabricate a simple phonon rectifier. The smaller of the two connected nanoparticles imposes stronger phonon confinement leading to rectifying phonon transport. This concept is extended to the macroscale by constructing two overlapping layers of differently sized nanoparticles, thereby realizing a macroscopic phonon diode. Following the localized heat deposition by laser light, the temperature profiles across a phonon-diode were measured by infrared imaging. Although the rectifying strength is moderate, the abundance of optimization possibilities makes this method promising for ultra-low volume thermal insulation at both the nano- and macroscale

cond-mat.mtrl-sci↗

arXiv2015

Multipole plasmons and their disappearance in few-nanometer silver nanoparticles

In electron energy-loss spectroscopy (EELS) of individual silver nanoparticles encapsulated in silicon nitride, we observe besides the usual dipole resonance an additional surface plasmon (SP) resonance corresponding to higher angular momenta. We even observe both resonances for nanoparticle radii as small as 4 nm, where previously only the dipole resonance was assumed to play a role. Electron beams positioned outside of the particles mostly excite the dipole mode, but the higher-order resonance can even dominate the dipole peak when exciting at the particle surface, the usual choice for maximal EELS signal. This allows us to study the radius dependence of both resonances separately. For particles smaller than 4 nm, the higher-order SP mode disappears, in agreement with generalized nonlocal optical response (GNOR) theory, while the dipole resonance blueshift exceeds GNOR predictions. Unlike in optical spectra, multipole surface plasmons are important in EELS spectra even of ultra-small metallic nanoparticles.

physics.optics↗