Off-Stoichiometry Driven Carrier Density Variation at the Interface of LaAlO3/SrTiO3

Abstract The interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted enormous interests due to its rich physical phenomena, such as metallic nature, magnetism and superconductivity. In this work, we report our experimental investigations on the influence of the LAO stoichiometry to the metalli...

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Bibliographic Details
Main Authors: Ming-Shiu Tsai, Chi-Sheng Li, Shih-Ting Guo, Ming-Yuan Song, Akhilesh Kr. Singh, Wei-Li Lee, M.-W. Chu
Format: Article
Language:English
Published: Nature Publishing Group 2017-05-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-017-02039-x
Description
Summary:Abstract The interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted enormous interests due to its rich physical phenomena, such as metallic nature, magnetism and superconductivity. In this work, we report our experimental investigations on the influence of the LAO stoichiometry to the metallic interface. Taking advantage of the oxide molecular beam epitaxy (MBE) technique, a series of high quality LAO films with different nominal La/Al ratios and LAO thicknesses were grown on the TiO2-terminated STO substrates, where systematic variations of the LAO lattice constant and transport property were observed. In particular, the sheet density can be largely reduced by nearly an order of magnitude with merely about 20% increase in the nominal La/Al ratio. Our finding provides an effective method on tuning the electron density of the two-dimensional electron liquid (2DEL) at the LAO/STO interface.
ISSN:2045-2322