Phonon-Induced Wake Potential in a Graphene-Insulator -Graphene Structure.

The aim of this study is to explore the potential which arises in a graphene-insulator-graphene structure when an external charged particle is moving parallel to it with a speed smaller than the Fermi speed in graphene. This is achieved by employing the dynamic polarization function of graphene within the random phase approximation, where its π electrons are modeled as Dirac fermions, and utilizing a local dielectric function for bulk insulators. Three different insulators are considered: SiO, HfO, and AlO.

A Comprehensive Mechanical Examination of ABS and ABS-like Polymers Additively Manufactured by Material Extrusion and Vat Photopolymerization Processes.

Additive manufacturing technologies have developed rapidly in recent decades, pushing the limits of known manufacturing processes. The need to study the properties of the different materials used for these processes comprehensively and in detail has become a primary goal in order to get the best out of the manufacturing itself. The widely used thermoplastic polymer material acrylonitrile butadiene styrene (ABS) was selected in the form of both filaments and ABS-like resins to investigate and compare the mechanical properties through a series of different tests.

Energy loss of charged particles in anisotropic 2D materials using the oscillator model.

We apply the oscillator model to study the energy loss processes of external charged particles interacting with a 2D material characterized by an anisotropic conductivity tensor. We model the material as a monolayer of harmonic oscillators, with anisotropic electronic vibration modes. We focus on the cases of parallel and perpendicular trajectories of the external particle, and we obtain analytical expressions for the stopping power and total energy loss in terms of reduced variables.

Launching Plasmons in a Two-Dimensional Material Traversed by a Fast Charged Particle.

We use a dielectric-response formalism to compute the induced charge density and the induced potential in a conductive two-dimensional (2D) material, traversed by a charged particle that moves on a perpendicular trajectory with constant velocity. By analyzing the electric force on the material via the Maxwell stress tensor, we showed that the polarization of the material can be decomposed into a conservative part related to the dynamic image force, and a dissipative part describing the energy and momentum transfer to the material, which is ultimately responsible for launching the plasma oscillation waves in the material. After showing that the launching dynamics is fully determined by the Loss function of the material, we used a conductivity model suitable for the terahertz to the midinfrared frequency range, which includes both the intraband and interband electron transitions in the material, to compute the real-space and time animations of the propagating plasma waves in the plane of the material.

Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals.

Graphene doped by alkali atoms (ACx) supports two heavily populated bands (π and σ) crossing the Fermi level, which enables the formation of two intense two-dimensional plasmons: the Dirac plasmon (DP) and the acoustic plasmon (AP). Although the mechanism of the formation of these plasmons in electrostatically biased graphene or at noble metal surfaces is well known, the mechanism of their formation in alkali-doped graphenes is still not completely understood. We shall demonstrate that two isoelectronic systems, KC8 and CsC8, support substantially different plasmonic spectra: the KC8 supports a sharp DP and a well-defined AP, while the CsC8 supports a broad DP and does not support an AP at all.