相关论文: Positronium formation in graphene and graphite

We investigate the elastic and inelastic scattering of positrons by sodium atoms in both the ground state, Na($3s$), and excited states, Na*($3p$, $4s$, $3d$), using the hyperspherical coordinate method with a model potential to represent…

The excess energy emitted during the positronium (Ps) formation in condensed matter may be released as light. Spectroscopic analysis of this light can be a new method of studying the electronic properties of materials. We report the first…

When recent experimental positronium (Ps) formation cross sections in noble gases have been compared with the most up-to date theoretical studies, the agreement is qualitative, but not quantitative. In this paper we re-examine this process…

We present Doppler broadened gamma spectra, obtained using the newly developed advanced positron beam at the University of Texas at Arlington, from a sample consisting of 6 to 8 layers of graphene (MLG) on polycrystalline Cu. The kinetic…

We present a monoenergetic positron beam specifically tailored to the needs of (near-) surface positron annihilation spectroscopy. The Setup for LOw-energy Positron Experiments (SLOPE) comprises a high-activity 22Na source, a tungsten…

The surface structure of Few-Layer Graphene (FLG) epitaxially grown on the C-face of SiC has been investigated by TM-AFM in ambient air and upon interaction with diluted aqueous solutions of bio-organic molecules (dimethyl sulfoxide, DMSO,…

The comparison of different models (the Ore, spur and blob models) of positronium (Ps) formation is presented. Because in molecular media Ps is formed in the terminal positron blob and not in an ordinary spur, the application of the blob…

Producing positronium (Ps) in the metastable $2^3\text{S}$ state is of interest for various applications in fundamental physics. We report here about an experiment in which Ps atoms are produced in this long-lived state by spontaneous…

Harnessing electronic excitations involving coherent coupling to bosonic modes is essential for the design and control of emergent phenomena in quantum materials [1]. In situations where charge carriers induce a lattice distortion due to…

The formation of self-organized laser induced periodic surface structures (LIPSS) in metals, semiconductors and dielectrics upon pulsed laser irradiation is a well-known phenomenon, receiving increased attention due to its huge…

Antihydrogen production by charge exchange reaction between Positronium (Ps) atoms and antiprotons requires an efficient excitation of Ps atoms up to high-n levels (Rydberg levels). In this study it is assumed that a Ps cloud is produced…

We present a computational study of the laser-driven quantum dynamics of positronium (Ps), PsH, and PsCl at the time-dependent Hartree-Fock level of theory. To eliminate finite-basis effects and to properly capture continuum dynamics, we…

Positronium (Ps) has emerged as a promising test particle within the QUPLAS collaboration for investigating the gravitational effect. In this work, we present a novel approach to generate a monoenergetic and highly coherent Ps beam by…

In this paper, we present and analyze measurements of the positron induced electron spectra (PIES) from highly oriented pyrolytic graphite (HOPG). The spectra were obtained using a time of flight spectrometer attached to a variable energy…

We investigate dilepton production in heavy-ion, proton-proton, and proton-nucleus collisions from low energies of 1 AGeV (SIS) to ultra-relativistic energies (LHC) using the Parton-Hadron-String Dynamics (PHSD) transport approach. PHSD is…

This chapter reviews the following items: 1. Energy deposition and track structure of fast positrons: ionization slowing down, number of ion-electron pairs, typical sizes, thermalization, electrostatic interaction between e+ and its blob,…

Surface plasmon polaritons (SPPs) can be understood as two-dimensional light confined to a conductor-dielectric interface via plasmonic excitations. While low-energy SPPs behave similarly to photons, higher-frequency SPPs resemble surface…

We present a first principles-quality potential energy surface (PES) describing the inter-atomic forces for hydrogen atoms interacting with free-standing graphene. The PES is a high-dimensional neural network potential that has been…

Materials with graphene-like layers attract tremendous attention due to their electronic structures and superconducting properties. In this study, we synthesized LaP2 polycrystalline and observed a superconducting transition around 30 GPa.…

The development of radiation-tolerant materials capable of maintaining structural, electrical, and thermal stability in extreme, radiation-rich environments remains a critical challenge in materials science. In this work, the effects of 60…