Interaction of relativistic charged particles with 2D materials. Application to graphene.

GERVASONI J. L.; SEGUI, S.; ARISTA N R; MISKOVIC, ZORAN L

Evento on-line

Conferencia; Condensed Matter and Quantum Materials Institute of Physics (QMCM2021); 2021

Institute of Physics

2D materials are a subject of intense research in different areas due to their unique properties and applications. In this work we present a comprehensive framework to study the response of a monoatomic layer to external charged particles, adapting an oscillators model to describe the behavior of the atomic array. We calculate the energy loss of relativistic charged particles (electrons and heavy ions) impinging on a2D-material sheet, represented as a planar array of harmonic oscillators, with electronic vibration modes of characteristic frequencies i. The incident particle travels along a rectilinear trajectory either parallel or perpendicular to the layer, and transfers energy to the oscillators through its electromagnetic field. Using this simple model, we obtain several useful analytical expressions for the energy loss as a function of the relevant parameters of the process.We apply this model to the case of graphene, one of the most representative and interesting 2D material. We consider two regimes of oscillators frequencies: the optical range, where the interband electron transitions give rise to the characteristic frequencies of Pi and Sigma oscillators around 4 and 14eV; and the THz range of frequencies, relevant for the case of doped graphene where intraband Pi-electrons excitations give raise to astrongly dispersing sheet plasmon-polariton mode [2]. In both regimes, we obtain the stopping power and total energy loss for parallel and perpendicular trajectories respectively.We observe that the oscillators model is in very good agreement with other very well known methods [3] on a wide range of velocities and impact parameters. We remark that this versatile model gives a promising alternative description of the incident particle energy loss in 2D-materials with their respective distinctive properties.