Speaker
Description
The direct detection of dark-matter mainly relies on the nuclear recoil energy in detector materials, where only a fraction of the recoil energy contributes to measurable ionization or scintillation signals. This fraction is termed as the quenching factor (QF) and is an essential parameter to reconstruct the nuclear recoil energy accurately. Lindhard's model provides a theoretical framework to calculate the quenching factor and SRIM framework is used to simulate for the electronic and nuclear energy loss in the materials. However, both of these methods, suffer from growing uncertainties specially in the sub-keV regime, where the sensitivity of light Dark-Matter is the most critical [1,2].
In this work, we present a classical molecular dynamics based framework to investigate the recoil energy loss and quenching factor in Silicon. For this work,a simulation cell of (20x20x20) lattice units with periodic boundary conditions is created. We adpot here, a modified tersoff-potential which precisely incorporates the Many-Body effects [3]. The preliminary results reveal systematic deviations from Lindhard’s model and are closer to experimental data between 20 eV to 10 keV energy range. This is highlighting the capability of MD-framework to capture the underlying atomistic processes such as defect formation, phonon excitations and lattice binding effects.
