Long-Range Surface Reconstruction:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">S</mml:mi><mml:mi mathvariant="normal">i</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>110</mml:mn><mml:mo stretchy="false">)</mml:mo><mml:mtext mathvariant="normal">−</mml:mtext><mml:mo stretchy="false">(</mml:mo><mml:mn>16</mml:mn><mml:mo>×</mml:mo><mml:mn>2</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>

A variety of reconstruction models is studied for the Si(110)-(16 x 2) surface using first-principles calculations. Assuming appropriate rebonding of edge atoms and surface chains buckled in antiphase, we show that steps along the [112] direction yielding a trench indeed lower the surface energy. We explain the long-range surface reconstruction and develop a geometry model based on steps, adatoms, tetramers, and interstitials. The model is able to explain the stripes of paired pentagons seen obviously in empty-state scanning tunneling microscopy images.