Native defects in germanium

Abstract

We study, using first principles calculations, the electronic and structural properties of an isolated vacancy and self-interstitial defects in germanium. For the vacancy we analyze the lattice relaxations for the charge states (++), (+), and (0), and show that the atomic displacements, albeit small, are not completely negligible for the second-nearest-neighbor atoms to the vacancy site. Moreover, we show that the relaxations decay slowly along the zigzags that go through the vacancy site. For the self-interstitial we present an analysis of the charge density, which supports the description of this defect as a four-atoms ring strongly attached to the lattice, which we have named a kite-defect.