Structural Model for Single Links of TiO₂(110)-(1×2) Surface from Analyses of Scanning Tunneling Microscopy and Density Functional Theory Calculations

Rutile TiO₂(110) is widely regarded as the prototypical metal oxide surface in surface science. For decades, the structural description of its reconstructed (1×2) link region was built upon the implicit assumption of structural symmetry, until very recent studies revealed that the (1×2) reconstruction itself is intrinsically asymmetric, rendering all earlier symmetric link region models need to be improved. Motivated by this, this work carries out a systematic reinvestigation of the link-region atomic structure through a synergistic combination of high-resolution scanning tunneling microscopy experiments and first-principles density functional theory calculations. We generate a comprehensive set of candidate models constrained by the newly confirmed asymmetric (1×2) geometry, perform full structural relaxation, and then carry out a systematic validation procedure by matching Tersoff-Hamann simulated STM images with experimental micrographs. Ultimately, this procedure yields the optimal, experimentally consistent atomic structure of the link region.