Bandgap Controlling of the Oxygen-Vacancy-Induced Two-Dimensional Electron Gas in SrTiO3

Abstract

We report very large bandgap enhancement in SrTiO3 (STO) films (fabricated by pulsed laser deposition below 800 °C), which can be up to 20% greater than the bulk value, depending on the deposition temperature. The origin is comprehensively investigated and finally attributed to Sr/Ti antisite point defects, supported by density functional theory calculations. More importantly, the bandgap enhancement can be utilized to tailor the electronic and magnetic phases of the two-dimensional electron gas (2DEG) in STO-based interface systems. For example, the oxygen-vacancy-induced 2DEG (2DEG-V) at the interface between amorphous LaAlO3 and STO films is more localized and the ferromagnetic order in the STO-film-based 2DEG-V can be clearly seen from low-temperature magnetotransport measurements. This opens an attractive path to tailor electronic, magnetic and optical properties of STO-based oxide interface systems under intensive focus in the oxide electronics community. Meanwhile, our study provides key insight into the origin of the fundamental issue that STO films are difficult to be doped into the fully metallic state by oxygen vacancies.

arXiv comment35 pages, 6 figures in the main text,13 figures in the supporting information. To be appearing in Advanced Materials Interfaces soon

References in corpus (20)

• Magnetic effects at the interface between nonmagnetic oxides
• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Coexistence of superconductivity and ferromagnetism in two dimensions
• Metallic and insulating interfaces of amorphous SrTiO3-based oxide heterostructures
• Superconductivity and Ferromagnetism in Oxide Interface Structures: Possibility of Finite Momentum Pairing
• Critical thickness for ferromagnetism in LaAlO3/SrTiO3 heterostructures
• Magnetism and superconductivity at LAO/STO-interfaces: the role of Ti 3d interface electrons
• Carrier freeze-out induced metal-insulator transition in oxygen deficient SrTiO3 films
• Oxygen vacancies at titanate interfaces: two-dimensional magnetism and orbital reconstruction
• Nature of weak magnetism in SrTiO3/LaAlO3 multilayers
• Reversible room-temperature ferromagnetism in Nb-doped SrTiO3 single crystals
• Localization of Two-dimensional Electron Gas in LaAlO3/SrTiO3 Heterostructures
• Cationic vacancy induced room-temperature ferromagnetism in transparent conducting anatase Ti_{1-x}Ta_xO_2 (x~0.05) thin films
• Magnetic-field induced resistivity minimum with in-plane linear magnetoresistance of the Fermi liquid in SrTiO3-x single crystals
• Fabricating Superconducting Interfaces between Artificially-Grown LaAlO${}_3$ and SrTiO${}_3$ Thin Films
• Nonlinear Insulator in Complex Oxides
• Reversible metal-insulator transition in LaAlO3 thin films mediated by intragap defects: An alternative mechanism for resistive switching
• Chemistry and structure of homoepitaxial SrTiO${}_3$ films and their influence on oxide-heterostructure interfaces
• The Conducting Channel at the LaAlO${}_3$/SrTiO${}_3$ Interface
• Atomically flat interface between a single-terminated LaAlO3 substrate and SrTiO3 thin film is insulating

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