  Recent progress in phonon-mediated detectors with eV-scale nuclear recoil
energy sensitivity requires an understanding of the effect of the crystalline
defects on the energy spectrum expected from dark matter or neutrino coherent
scattering. We have performed molecular dynamics simulations to determine the
amount of energy stored in the lattice defects as a function of the recoil
direction and energy. This energy can not be observed in the phonon
measurement, thus affecting the observed energy spectrum compared to the
underlying true recoil energy spectrum. We describe this effect for multiple
commonly used detector materials and demonstrate how the predicted energy
spectrum from dark matter scattering is modified.
