First-principles calculation of as atomic wires on a H-terminated Si(100) surface

The atomic and electronic structures of As atomic wires, which are formed by As adsorbates around a dangling-bond wire on a II-terminated Si(100), are investigated by using first-principles calculations within the local-density-functional approach. By comparing the metastable geometries of the As atomic wires with those of the Ga atomic wires previously studied,we found that As atoms have a stronger tendency to form covalent bonds. Interestingly, the most stable As configuration has an energy band with no significant dispersion as the lowest empty surface state. Electron-doping into this flat band may open up the possibility to form a ferromagnetic atomic wire. To exemplify such doping, we show that a half-filled flat band can be realized, its flatness unchanged, when K adsorbates are supplied to the As wire. [S0163-1829(99)03927-2].