Dichotomy of the photo-induced 2-dimensional electron gas on SrTiO ₃ surface terminations

Abstract

Significance Titanates are a group of oxide materials which are heavily studied due to their wide array of interesting physical properties. Here, we study the origin of one particular property, the 2-dimensional electron gas (2DEG), by growing SrTiO 3 and other titanate films with different surface terminations, using atomic layer-by-layer growth and probing their electronic structures. Surprisingly, we only observe the 2DEG on the A-site termination and not on the B-site termination. We use this dichotomy to help understand the origin of the 2DEG and suggest how this same methodology could be applied to other oxide systems.