Ground-state properties of arsenic deposited on the Ge(0 0 1)(2 × 1) surface

We present results of ab initio calculations of structural, electronic and vibrational properties of the Ge(0 0 1) surface covered with a monolayer of arsenic. The fully occupied πu bonding and πg antibonding electronic states due to the As-As dimer formation are quite close in energy and their ordering is same as that found on the Si(0 0 1) surface. Using our calculated atomic and electronic structures, surface lattice dynamics was studied by employing a linear response approach based on density functional perturbation theory. A comparison of the phonon spectrum of the Ge(0 0 1)/As(2 × 1) surface with that of the clean Ge(0 0 1)(2 × 1) surface indicates the presence of several new characteristic phonon modes due to adsorption of As atoms.