In situ investigation of conducting interface formation in LaAlO3/SrTiO3 heterostructure

Abstract

The high-mobility conducting interface (CI) between LaAlO_{3}(LAO) and SrTiO_{3}(STO) has revealed many fascinating phenomena, including exotic magnetism and superconductivity. But, the formation mechanism of the CI has not been conclusively explained. Here, using in situ angle-resolved photoemission spectroscopy, we elucidated the mechanisms for the CI formation. In as-grown samples, we observed a built-in potential (V_{bi}) proportional to the polar LAO thickness starting from the first unit cell (UC) with CI formation appearing above 3 UCs. However, we found that the V bi is removed by synchrotron ultraviolet (UV)-irradiation; The built-in potential is recovered by oxygen gas (O_{2}(g))-exposure. Furthermore, after UV-irradiation, the CI appears even below 3UC of LAO. Our results demonstrate not only the V_{bi}-driven CI formation in asgrown LAO/STO, but also a new route to control of the interface state by UV lithographic patterning or other surface modification.

18 pages, 4 figures

References in corpus (7)

• Magnetic effects at the interface between nonmagnetic oxides
• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Surface defects and conduction in polar oxide heterostructures
• Origin of Metallic States at Heterointerface between Band Insulators LaAlO${}_3$ and SrTiO${}_3$
• Gate-tunable band structure of the LaAlO${}_3$-SrTiO${}_3$ interface
• Enhanced tunability of two-dimensional electron gas on SrTiO3 through heterostructuring

Cited by in corpus (1)

• Direct visualization and control of SrOx segregation on semiconducting Nb doped SrTiO3 (100) surface