Phase Diagram of Adsorbate-Induced Row-Type-Alignments

The phase diagram of adsorbate-induced row-type-alignments, such as missing-row reconstructions induced by adsorbate-atoms on the FCC(110) surface, is calculated by the Blume-Emmery-Griffiths (BEG) model. In the model, we introduce adatom-adatom and dipole-dipole interactions between nearest-neighbor (NN) and next-nearest-neighbor (NNN) rows. The calculation of the temperature versus adatom chemical potential phase diagram is performed using mean-field approximation. It is indicated that when NN and NNN interactions are competitive, there appear either dipole or coverage modulated (incommensurate) phases at high temperatures for wide regime of the interactions.