Retention of Electronic Conductivity in LaAlO3/SrTiO3 Nanostructures Using a SrCuO2 Capping Layer
Artikel i vetenskaplig tidskrift, 2016

The interface between two wide band-gap insulators, LaAlO3 and SrTiO3 (LAO/STO) offers a unique playground to study the interplay and competitions between different ordering phenomena in a strongly correlated two- dimensional electron gas. Recent studies of the LAO/STO interface reveal the inhomogeneous nature of the 2DEG that strongly influences electrical-transport properties. Nanowires needed in future applications may be adversely affected, and our aim is, thus, to produce a more homogeneous electron gas. In this work, we demonstrate that nanostructures fabricated in the quasi-2DEG at the LaAlO3/SrTiO3 interface, capped with a SrCuO2 layer, retain their electrical resistivity and mobility independent of the structure size, ranging from 100 nm to 30 mu m. This is in contrast to noncapped LAO/STO structures, where the room-temperature electrical resistivity significantly increases when the structure size becomes smaller than 1 mu m. High-resolution intermodulation electrostatic force microscopy reveals an inhomogeneous surface potential with "puddles" of a characteristic size of 130 nm in the noncapped samples and a more uniform surface potential with a larger characteristic size of the puddles in the capped samples. In addition, capped structures show superconductivity below 200 mK and nonlinear currentvoltage characteristics with a clear critical current observed up to 700 mK. Our findings shed light on the complicated nature of the 2DEG at the LAO/STO interface and may also be used for the design of electronic devices.

Författare

Pier Paolo Aurino

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Alexei Kalaboukhov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

R. Borgani

D. B. Haviland

Thilo Bauch

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Floriana Lombardi

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Tord Claeson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Dag Winkler

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Physical Review Applied

2331-7019 (eISSN)

Vol. 6 2

Ämneskategorier

Fysik

DOI

10.1103/PhysRevApplied.6.024011

Mer information

Skapat

2017-10-08