1 Department of Energy Conversion and Storage, Technical University of Denmark2 Electrofunctional materials, Department of Energy Conversion and Storage, Technical University of Denmark3 Chinese Academy of Sciences
Our recent experimental work on metallic and insulating interfaces controlled by interfacial redox reactions in SrTiO3-based heterostructures is reviewed along with a more general background of two-dimensional electron gas (2DEG) at oxide interfaces. Due to the presence of oxygen vacancies at the SrTiO3 surface, metallic conduction can be created at room temperature in perovskite-type interfaces when the overlayer oxide ABO3 has Al, Ti, Zr, or Hf elements at the B sites. Furthermore, relying on interface-stabilized oxygen vacancies, we have created a new type of 2DEG at the heterointerface between SrTiO3 and a spinel g-Al2O3 epitaxial film with compatible oxygen ion sublattices. This 2DEG exhibits an electron mobility exceeding 100000 cm2·V-1·s-1, more than one order of magnitude higher than that of hitherto investigated perovskite-type interfaces. Our findings pave a way for the design of high-mobility all-oxide electronic devices and open a route toward the studies of mesoscopic physics with complex oxides.
Chinese Physics B, 2013, Vol 22, Issue 11
Oxide interfaces; Two-dimensional electron gas (2DEG); SrTiO3; Oxygen vacancies