Direct in Situ Determination and Modulation of Asymmetric Surface Reconstruction on Rutile TiO2

Abstract

Abstract Rutile TiO2 (110)-(1×2) reconstructions have triggered long time debate due to the conflicts among different experimental observations. Here, by combining state-of-the-art in situ spherical aberration corrected scanning transmission electron microscopy and density functional theory calculations, we unravel the asymmetric surface reconstruction of rutile TiO2 (110)-(1×2). We conclude that the repulsive electrostatic interaction among the small polarons, formed by the excess electrons after removal of neutral oxygen, and the consequent small polaron induced surface relaxations play critical roles in the asymmetric surface reconstruction. Importantly, the emergence and dissolution of these asymmetric structures can be modulated by tuning the oxygen partial pressure. This research offers an innovative approach to better understand, predict, and control surface reconstructions, holding significant implications for various applications and technological advancements.