Speaker
Description
Electron energy-loss spectroscopy (EELS) is an experimental technique used in transmission electron microscopy to probe single-particle and collective excitations, including excitons and plasmons. Momentum-resolved EELS goes beyond studying the energies of these excitations by revealing their dispersion as a function of momentum transfer, an important physical quantity. Experimental spectra reveal these effects, however, their full interpretation requires a quantitative theoretical description. For this reason, we employ computationally demanding first-principles calculations based on density functional theory (DFT) and many-body perturbation theory (MBPT). We focus on molybdenum disulfide, a representative of transition-metal dichalcogenide, with important optoelectronic properties, including an indirect-to-direct band-gap transition. Its ground-state properties are calculated using DFT and MBPT, while the energy-loss function is currently computed using time-dependent DFT. This work demonstrates how high-performance computing can connect experiment and theory, helping to uncover the underlying electronic properties of low-dimensional materials.