title: Nanoscale control of an interfacial metal-insulator transition at room temperature.
abstract: Experimental and theoretical investigations have demonstrated that a quasi-two-dimensional electron gas (q-2DEG) can form at the interface between two insulators: non-polar SrTiO3 and polar LaTiO3 (ref. 2), LaAlO3 (refs 3-5), KTaO3 (ref. 7) or LaVO3 (ref. 6). Electronically, the situation is analogous to the q-2DEGs formed in semiconductor heterostructures by modulation doping. LaAlO3/SrTiO3 heterostructures have recently been shown to exhibit a hysteretic electric-field-induced metal-insulator quantum phase transition for LaAlO3 thicknesses of 3 unit cells. Here, we report the creation and erasure of nanoscale conducting regions at the interface between two insulating oxides, LaAlO3 and SrTiO3. Using voltages applied by a conducting atomic force microscope (AFM) probe, the buried LaAlO3/SrTiO3 interface is locally and reversibly switched between insulating and conducting states. Persistent field effects are observed using the AFM probe as a gate. Patterning of conducting lines with widths of approximately 3 nm, as well as arrays of conducting islands with densities >10(14) inch(-2), is demonstrated. The patterned structures are stable for >24 h at room temperature.
authors.affiliation: Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara St, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: C
authors.initials: C
authors.lastname: Cen
authors.forename: S
authors.initials: S
authors.lastname: Thiel
authors.forename: G
authors.initials: G
authors.lastname: Hammerl
authors.forename: C W
authors.initials: CW
authors.lastname: Schneider
authors.forename: K E
authors.initials: KE
authors.lastname: Andersen
authors.forename: C S
authors.initials: CS
authors.lastname: Hellberg
authors.forename: J
authors.initials: J
authors.lastname: Mannhart
authors.forename: J
authors.initials: J
authors.lastname: Levy