Two-dimensional superconductivity between SrTiO3 and amorphous Al2O3

Abstract

Properties of stacked SrTiO3/Al2O3 metal-insulator-metal capacitorsTwo-dimensional (2D) superconductivity is observed between insulating amorphous Al 2 O 3 and TiO 2 -terminated (001)-oriented SrTiO 3 . The heterostructure displays interfacial metallic conduction from room temperature down to %200 mK where superconductivity sets in. The voltage-current V(I) characteristics indicate a power-law scaling behavior V / I a with a temperature dependent exponent a, indicative for a Berezinskii-Kosterlitz-Thouless transition at T BKT % 160 mK and a 2D superconducting state. The superconducting transition was found to be very sensitive to a magnetic field B. V C 2014 AIP Publishing LLC. [http://dx.

Temperature dependent giant resistance anomaly in LaAlO3/SrTiO3 nanostructures

“…Nanostructures with a width of less than 500 nm, however, always show some peak in resistance. It should be noted that there are such observations by a number of groups 6, 29, 30 , who have observed a monotonic drop in resistance during cool-down and small non monotonicities in resistance during warm-up in a large area sample, however, the authors could give no explanation. These results will be discussed later.…”

Anisotropic electronic transport of the two-dimensional electron system in Al2O3/SrTiO3 heterostructures

“…The single-type termination of the STO substrates usually leads to the formation of a stepped surface with a step-height of one STO unit cell [21]. Motivated by previous observations of the possible influence of interfacial steps on the anisotropic transport behavior [22,12] we used substrates with different step edge alignment with respect to the [100] direction. For sample I, the angle between the step edges and the [100] direction amounts to ω ≈ 85° and for sample II ω ≈ 55°.…”

“…In the used current-and temperature-regime the contacts showed clear Ohmic behavior. More details with respect to sample preparation are given in references [12,20]. The single-type termination of the STO substrates usually leads to the formation of a stepped surface with a step-height of one STO unit cell [21].…”

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

“…Finally, we demonstrated devices implementing local electrostatic gate-control of the carrier density in narrow constrictions. Various aspects of the patterning approach were demonstrated using room temperature grown amorphous LAO as the top-layer; however, alternative STO-based conducting room temperature grown interfaces have been reported, 16,18 and we expect that the techniques reported in this study may be directly applied to such systems as well. The results present a simple way to bridge the gap between oxide-based quantum device fabrication and state-of-the-art semiconductor processing.…”

“…16 The key properties of gate-tunability and gatetunable superconductivity, 17,18 however, remain intact, and moreover, the highest transition temperature reported for the STO-based 2DES was achieved in the a-LAO/STO system. 19 Also, recently, studies were performed on the transport properties of negative-U quantum dot devices which were fabricated from a-LAO/STO heterostructures.…”