Electron-Energy-Loss Spectra of Free-Standing Silicene

TL;DR

This study calculates electron-energy-loss spectra for flat and buckled silicene using tight-binding and RPA methods, revealing unique resonances and effects of buckling on spectral features.

Contribution

It introduces detailed EEL spectra calculations for silicene, considering different structures and advanced computational methods, highlighting the impact of buckling.

Findings

Additional resonances compared to bulk silicon

Red-shifted spectral features

Buckling enriches low-energy spectral structure

Abstract

Silicene is becoming one of the most important two-dimensional materials. In this work, EEL Spectra were calculated for alfa-silicene (flat), and beta-silicene (low-buckled, and theoretically the most stable). Band structures were determined using the semi-empirical Tight-Binding Method considering second nearest neighbors, sp3 model, Harrison's rule, and Slater-Koster parameterization. The dielectric function was calculated within the Random Phase Approximation and a space discretization scheme. We found that, compared to bulk Si, additional resonances appear which are red-shifted. Buckling gives rise to a richer structure at low energy.