The atomic and electronic structures of the dissociative adsorption of ammonia on the $\mathrm{Si}\mathrm{}\left(100\right)\mathrm{}-(2\mathrm{}\times 1)$ surface are studied by first-principles calculations. We find that the hydrogen-bonding interactions between the dissociated ${\mathrm{NH}}_2$ species favor the “gauche” model over the existing models. This strong attractive force can form a one-dimensional hydrogen-bonded array of ${\mathrm{NH}}_2$ along the Si dimer row. Our analysis identifies three ${\mathrm{NH}}_2$-derived electronic states, composed of one delocalized state along the dimer row and two localized molecular orbitals.

• Received 4 April 2000

DOI:https://doi.org/10.1103/PhysRevB.62.1607