Electrical and structural properties of ABO3/SrTiO3 interfaces

Alexei Kalaboukhov; Tord Claeson; Pier Paolo Aurino; Robert Gunnarsson; Dag Winkler; Eva Olsson; Nikolina Tuzla; Johan Börjesson; Yu A. Boikov; I.T. Serenkov; V.I. Sakharov; M. P. Volkov

doi:10.1557/opl.2012.925

Electrical and structural properties of ABO3/SrTiO3 interfaces
Paper in proceedings, 2012

Electrical transport and microstructure of interfaces between nm-thick films of various perovskite oxides grown by pulsed laser deposition (PLD) on TiO2 terminated SrTiO3 (STO) substrates are compared. LaAlO3/STO and KTaO3/STO interfaces become quasi-2DEG after a critical film thickness of 4 unit cell layers. The conductivity survives long anneals in oxygen atmosphere. LaMnO3/STO interfaces remain insulating for all film thicknesses and NdGaO3/STO interfaces are conducting but the conductivity is eliminated after oxygen annealing. Medium-energy ion spectroscopy and scanning transmission electron microscopy detect cationic intermixing within several atomic layers from the interface in all studied interfaces. Our results indicate that the electrical reconstruction in the polar oxide interfaces is a complex combination of different mechanisms, and oxygen vacancies play an important role.