Controlling Kondo-like Scattering at the SrTiO3-based Interfaces

K Han; N Palina; S W Zeng; Z Huang; C J Li; W X Zhou; D-Y Wan; L C Zhang; X Chi; R Guo; J S Chen; T Venkatesan; A Rusydi; Ariando

doi:10.1038/srep25455

Controlling Kondo-like Scattering at the SrTiO3-based Interfaces

Sci Rep. 2016 May 5:6:25455. doi: 10.1038/srep25455.

Authors

K Han^{1

2}, N Palina^{1

3}, S W Zeng^{1

2}, Z Huang¹, C J Li¹, W X Zhou^{1

2}, D-Y Wan^{1

2}, L C Zhang^{1

2}, X Chi³, R Guo^{1

4}, J S Chen⁴, T Venkatesan^{1

2

4

5

6}, A Rusydi^{1

2

3}, Ariando^{1

2

6}

Affiliations

¹ NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore.
² Department of Physics, National University of Singapore, Singapore 117542, Singapore.
³ Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
⁴ Department of Material Science &Engineering, National University of Singapore, Singapore 117575, Singapore.
⁵ Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore.
⁶ National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), 28 Medical Drive, Singapore 117456, Singapore.

Abstract

The observation of magnetic interaction at the interface between nonmagnetic oxides has attracted much attention in recent years. In this report, we show that the Kondo-like scattering at the SrTiO3-based conducting interface is enhanced by increasing the lattice mismatch and growth oxygen pressure PO2. For the 26-unit-cell LaAlO3/SrTiO3 (LAO/STO) interface with lattice mismatch being 3.0%, the Kondo-like scattering is observed when PO2 is beyond 1 mTorr. By contrast, when the lattice mismatch is reduced to 1.0% at the (La0.3Sr0.7)(Al0.65Ta0.35)O3/SrTiO3 (LSAT/STO) interface, the metallic state is always preserved up to PO2 of 100 mTorr. The data from Hall measurement and X-ray absorption near edge structure (XANES) spectroscopy reveal that the larger amount of localized Ti(3+) ions are formed at the LAO/STO interface compared to LSAT/STO. Those localized Ti(3+) ions with unpaired electrons can be spin-polarized to scatter mobile electrons, responsible for the Kondo-like scattering observed at the LAO/STO interface.

Publication types

Research Support, Non-U.S. Gov't