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 int roduce adatom-adatom and dipole-dipole interactions between nearest-neighbo r (NN) and next-nearest-neighbor (NNN) rows. The calculation of the tempera ture 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 (incommensur ate) phases at high temperatures for a wide regime of the interactions.