A Two-Dimensional Electron Gas at the Sulfurized SrTiO3 Interface

Sulfurization is a promising anion dopant method for synthesizing new multifunctional materials from functional oxides. Unlike traditional doping approaches that modify cation sites, the anion-site doping by substituting oxygen with sulfur in oxides expands the scope of doping strategies and achieves significant control over functionalities. In this work, we created two-dimensional electron gas at the interface between disordered yttria-stabilized zirconia (YSZ) and sulfurized SrTiO₃ substrates. Under the mobility-optimized conditions, substrate sulfurization enhanced the Rashba spin–orbit field and electron mobility of the interfacial 2DEG by 45 and 77%, respectively. To our knowledge, this work provides the first experimental demonstration of a 2DEG in SrTiO₃-based oxysulfides, validating anion-site doping as a viable route for oxide interface engineering.