Not yet reviewed by Pith; the record is open.

Developing reliable methods for modulating the electronic structure of the two-dimensional electron gas (2DEG) in SrTiO3 is crucial for utilizing its full potential and inducing novel properties. Here, we show that relatively simple surface preparation reconstructs the 2DEG of SrTiO3 (STO) surface, leading to a Lifshitz-like transition. Combining experimental methods, such as angle-resolved photoemission spectroscopy (ARPES) and X-ray photoemission spectroscopy (XPS) with ab initio calculations, we find that the modulation of the surface band structures is primarily attributed to the reorganization of the chemical composition. In addition, ARPES experiments demonstrate that vacuum ultraviolet (VUV) light can be efficiently employed to alter the band renormalization of the 2DEG system and control the electron-phonon interaction (EPI). Our study provides a robust and straightforward route to stabilize and tune the low-dimensional electronic structure via the chemical degeneracy of the STO surface.