Energy loss of relativistic charged particles in 2D materials, using the oscillator Model

S SEGUI; J GERVASONI; N. ARISTA; Z. L. MISKOVIC

Evento on-line

Simposio; 27th. International Symposium on Ion-Atom Collisions (ISIAC2021); 2021

Universidad de Cluj-Napoca

In this work we present a fully relativistic formulation for the energy loss of an external charged particle interacting with a 2D material.We model this material as a monolayer of atoms represented by harmonic oscillators, with isotropic or anisotropic electronic vibration modes.Adapting the oscillator model from [1] to a mono-atomic layer, we derive relativistic analyticalexpressions as a function of the relevant parameters of the process.We develop the model for a wide range of incident energies and considering both parallel andperpendicular trajectories. We obtain several useful analytical expressions for the energy lossconsidering isotropic and anisotropic in-plane oscillators, for parallel and perpendicular trajectories ofthe particle.The results shown for stopping power and energy loss are analyzed for generic materials by the useof adequate normalization factors, absorbing the dependencies on the specific properties of thematerial, namely the oscillator's areal density η and their resonant frequency ω. In the perpendicularcase the total energy loss Eperpendicular depends on the value of the frequency ω due to the adiabaticbehaviour at large distances.We notice that in an anisotropic 2D-oscillators system, the energy loss due to single oscillator (andtherefore the integrated quantities as stopping power and total energy loss) presents a reduction withrespect to the isotropic case, especially in the parallel trajectory. We ascribe this effect to the loweravailability of oscillation modes, and hence to a reduction of the interaction channels.Finally, we remark that the present model stands out for its generality, and provides a directevaluation of the energy loss processes in a generic 2D material.