Enhancement of electron mobility at oxide interfaces induced by WO3 overlayers
arXiv:1704.06522 · doi:10.1021/acsami.7b13202
Abstract
Interfaces between complex oxides constitute a unique playground for 2D electron systems (2DES), where superconductivity and magnetism can arise from combinations of bulk insulators. The 2DES at the LaAlO3/SrTiO3 interface is one of the most studied in this regard, and its origin is determined by both the presence of a polar field in LaAlO3 and the insurgence of point defects, such as oxygen vacancies and intermixed cations. These defects usually reside in the conduction channel and are responsible for a decreased electronic mobility. In this work we use an amorphous WO3 overlayer to control the defect formation and obtain an increased electron mobility and effective mass in WO3/LaAlO3/SrTiO3 heterostructures. The studied system shows a sharp insulator-to-metal transition as a function of both LaAlO3 and WO3 layer thickness. Low-temperature magnetotransport reveals a strong magnetoresistance reaching 900% at 10 T and 1.5 K, the presence of multiple conduction channels with carrier mobility up to 80 000 cm2/Vs and an unusually high effective mass of 5.6 me. The amorphous character of the WO3 overlayer makes this a versatile approach for defect control at oxide interfaces, which could be applied to other heterestrostures disregarding the constraints imposed by crystal symmetry.
References in corpus (29)
- Why Some Interfaces Cannot be Sharp
- Electric Field Control of the LaAlO/SrTiO Interface Ground State
- Tunable Rashba spin-orbit interaction at oxide interfaces
- Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface
- Coexistence of Magnetic Order and Two-dimensional Superconductivity at LaAlO/SrTiO Interfaces
- The role of oxygen vacancies in SrTiO3 at the LaAlO3/SrTiO3 interface
- Non-saturating magnetoresistance in heavily disordered semiconductors
- Metal-insulator transition in two-dimensional electron systems
- Metallic and insulating interfaces of amorphous SrTiO3-based oxide heterostructures
- A high-mobility two-dimensional electron gas at the heteroepitaxial spinel/perovskite complex oxide interface of γ-Al2O3/SrTiO3
- A Universal Critical Density Underlying the Physics of Electrons at the LaAlO3/SrTiO3 Interface
- A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces
- Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces
- LaAlO3 stoichiometry found key to electron liquid formation at LaAlO3/SrTiO3 interfaces
- Enhanced effective mass in doped SrTiO3 and related perovskites
- Polaronic metal state at the LaAlO3/SrTiO3 interface
- Nonlinear Hall effect and multichannel conduction in LaTiO3/SrTiO3 superlattices
- Shubnikov-de Haas oscillations in SrTiO3\LaAlO3 interface
- Surface defects and conduction in polar oxide heterostructures
- Parallel electron-hole bilayer conductivity from electronic interface reconstruction
- Defect engineering in oxide heterostructures by enhanced oxygen surface exchange
- A variational pseudo-self-interaction correction approach: ab-initio description of correlated oxides and molecules
- Giant negative magnetoresistance driven by spin-orbit coupling at the LAO/STO interface
- Strong magnetoresistance induced by long-range disorder
- Giant Oscillating Thermopower at Oxide Interfaces
- Growth-induced electron mobility enhancement at the LaAlO/SrTiO interface
- Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy
- Tuning up or down the critical thickness in LaAlO3/SrTiO3 through in situ deposition of metal overlayers
- Large phonon-drag enhancement induced by narrow quantum confinement at the LaAlO3/SrTiO3 interface