Cation stoichiometry and electrical transport properties of the NdGaO 3 /(0 0 1)SrTiO 3 interface
Artikel i vetenskaplig tidskrift, 2015

The interface formed between two wide band-gap insulators, NdGaO 3 and SrTiO 3 renders metallic behavior, similar to the LaAlO 3 /SrTiO 3 interface. The interface conductivity depends strongly upon oxygen pressure during growth of the NdGaO 3 film and subsequent annealing in oxygen. The conductivity of a (10uc) NdGaO 3 /SrTiO 3 film, pulsed laser deposited at low (p O 2=10-4mbar) oxygen pressure, vanishes after annealing at 600 C in oxygen atmosphere. For a similar interface formed at high oxygen pressure (p O 2=0.3mbar), the metallic conductivity remains also after post annealing. Medium energy ion spectroscopy (MEIS) in random (non-channeling) direction showed that a substantial part of Ga is missing in films deposited at low pressure, while optimal stoichiometry is approached in films deposited at high pressure. Aligned (channeling) MEIS likewise show that the Ga/Nd ratio approaches the stoichiometric value as the pressure is increased from 10-4 to 0.3mbar. This is interpreted as due to gallium desorption from a growing film at high temperature and low oxygen pressure while the re-evaporation of gallium is considerably suppressed at higher pressure. We discuss the possible role of stoichiometry on electrical transport properties.

neodymium gallate

two-dimensional electron gas

strontium titanate

polar oxide interfaces

medium energy ion spectroscopy

Författare

Alexei Kalaboukhov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Iouri Boikov

Russian Academy of Sciences

I.T. Serenkov

Russian Academy of Sciences

V.I. Sakharov

Russian Academy of Sciences

Tord Claeson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Dag Winkler

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Journal of Physics Condensed Matter

0953-8984 (ISSN)

Vol. 27 25 Art. no. 255004- 255004

Ämneskategorier

Den kondenserade materiens fysik

DOI

10.1088/0953-8984/27/25/255004

PubMed

26020228