Threshold defect production in germanium determined by density functional theory molecular dynamics simulations

Abstract

We studied the threshold displacement energy in germanium using density functional theory molecular dynamics simulations. The average threshold energy over all lattice directions for creating stable Frenkel pairs was found to be (23±2stat±3syst) eV. In the lattice directions ⟨111⟩ and ⟨100⟩, the threshold energy was found to be (11.5±1.5syst) eV and (19.5±1.5syst) eV, respectively. In a notable fraction of all the studied directions, a bond defect was created with a lower threshold than a Frenkel pair. The average threshold energy for creating either a bond defect or a Frenkel pair was found to be (21±1stat±3syst) eV.