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Title: Structural and subband changes at the LaAlO{sub 3}/SrTiO{sub 3} interface investigated by two-dimensional correlation spectroscopy

Abstract

The interplay among many ground states in correlated electron materials, especially at the LaAlO{sub 3}/SrTiO{sub 3} interface is central in deeply understanding the physical characteristics and improving further applications of these materials. Here, we use two-dimensional infrared correlation spectroscopy to study the influence of magnetic fields and temperature on the mid-infrared spectral responsivity of the interface. The magnetic field plays the main role at temperatures below the transition temperature, T{sub C}. Two additional spectral peaks were identified at wavelengths of 2800 nm and 3400 nm, when compared with our prior studies. All of these response bands are related to the spin-orbit coupling effect and crystal structure changes. Detailed structural and subband changes in the interface are also investigated.

Authors:
; ; ; ;  [1];  [2];  [1]
  1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22493915
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 6; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ALUMINATES; COMPARATIVE EVALUATIONS; ELECTRON CORRELATION; GROUND STATES; INFRARED SPECTRA; INTERFACES; LANTHANUM COMPOUNDS; L-S COUPLING; MAGNETIC FIELDS; STRONTIUM TITANATES; TRANSITION TEMPERATURE; TWO-DIMENSIONAL CALCULATIONS; TWO-DIMENSIONAL SYSTEMS

Citation Formats

Feng, Xin, Zhao, Kun, E-mail: zhk@cup.edu.cn, Zhan, Hong-Lei, Xiang, Wen-Feng, Lu, Zhi-Qing, Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249, and Xiao, Li-Zhi. Structural and subband changes at the LaAlO{sub 3}/SrTiO{sub 3} interface investigated by two-dimensional correlation spectroscopy. United States: N. p., 2015. Web. doi:10.1063/1.4923239.
Feng, Xin, Zhao, Kun, E-mail: zhk@cup.edu.cn, Zhan, Hong-Lei, Xiang, Wen-Feng, Lu, Zhi-Qing, Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249, & Xiao, Li-Zhi. Structural and subband changes at the LaAlO{sub 3}/SrTiO{sub 3} interface investigated by two-dimensional correlation spectroscopy. United States. doi:10.1063/1.4923239.
Feng, Xin, Zhao, Kun, E-mail: zhk@cup.edu.cn, Zhan, Hong-Lei, Xiang, Wen-Feng, Lu, Zhi-Qing, Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249, and Xiao, Li-Zhi. Mon . "Structural and subband changes at the LaAlO{sub 3}/SrTiO{sub 3} interface investigated by two-dimensional correlation spectroscopy". United States. doi:10.1063/1.4923239.
@article{osti_22493915,
title = {Structural and subband changes at the LaAlO{sub 3}/SrTiO{sub 3} interface investigated by two-dimensional correlation spectroscopy},
author = {Feng, Xin and Zhao, Kun, E-mail: zhk@cup.edu.cn and Zhan, Hong-Lei and Xiang, Wen-Feng and Lu, Zhi-Qing and Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249 and Xiao, Li-Zhi},
abstractNote = {The interplay among many ground states in correlated electron materials, especially at the LaAlO{sub 3}/SrTiO{sub 3} interface is central in deeply understanding the physical characteristics and improving further applications of these materials. Here, we use two-dimensional infrared correlation spectroscopy to study the influence of magnetic fields and temperature on the mid-infrared spectral responsivity of the interface. The magnetic field plays the main role at temperatures below the transition temperature, T{sub C}. Two additional spectral peaks were identified at wavelengths of 2800 nm and 3400 nm, when compared with our prior studies. All of these response bands are related to the spin-orbit coupling effect and crystal structure changes. Detailed structural and subband changes in the interface are also investigated.},
doi = {10.1063/1.4923239},
journal = {AIP Advances},
number = 6,
volume = 5,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}
  • We have performed high field magnetotransport measurements to investigate the interface electron gas in a high mobility SrTiO{sub 3}/SrCuO{sub 2}/LaAlO{sub 3}/SrTiO{sub 3} heterostructure. Shubnikov-de Haas oscillations reveal several 2D conduction subbands with carrier effective masses of 0.9m{sub e} and 2m{sub e}, quantum mobilities of order 2000 cm{sup 2}/V s, and band edges only a few millielectronvolts below the Fermi energy. Measurements in tilted magnetic fields confirm the 2D character of the electron gas, and show evidence of inter-subband scattering.
  • Cited by 41
  • Recently a metallic state was discovered at the interface between insulating oxides, most notably LaAlO{sub 3} and SrTiO{sub 3}. Properties of this two-dimensional electron gas (2DEG) have attracted significant interest due to its potential applications in nanoelectronics. Control over this carrier density and mobility of the 2DEG is essential for applications of these unique systems, and may be achieved by epitaxial strain. However, despite the rich nature of strain effects on oxide materials properties, such as ferroelectricity, magnetism, and superconductivity, the relationship between the strain and electrical properties of the 2DEG at the LaAlO{sub 3}/SrTiO{sub 3} heterointerface remains largely unexplored.more » Here, we use different lattice constant single-crystal substrates to produce LaAlO{sub 3}/SrTiO{sub 3} interfaces with controlled levels of biaxial epitaxial strain. We have found that tensile-strained SrTiO{sub 3} destroys the conducting 2DEG, while compressively strained SrTiO{sub 3} retains the 2DEG, but with a carrier concentration reduced in comparison to the unstrained LaAlO{sub 3}/SrTiO{sub 3} interface. We have also found that the critical LaAlO{sub 3} overlayer thickness for 2DEG formation increases with SrTiO{sub 3} compressive strain. Our first-principles calculations suggest that a strain-induced electric polarization in the SrTiO{sub 3} layer is responsible for this behavior. The polarization is directed away from the interface and hence creates a negative polarization charge opposing that of the polar LaAlO{sub 3} layer. This behavior both increases the critical thickness of the LaAlO{sub 3} layer, and reduces carrier concentration above the critical thickness, in agreement with our experimental results. Our findings suggest that epitaxial strain can be used to tailor 2DEGs properties of the LaAlO{sub 3}/SrTiO{sub 3} heterointerface.« less
  • Two-dimensional electron gas (2DEG) formed at the interface between two oxide band-insulators LaAlO{sub 3} and SrTiO{sub 3} raises the possibility to develop oxide nanoelectronics. Here, we report the creation of a 2DEG at the LaAlO{sub 3}/SrTiO{sub 3} heterointerfaces grown by 90° off-axis sputtering which allows uniform films over a large area. The electrical transport properties of the LaAlO{sub 3}/SrTiO{sub 3} heterointerface are similar to those grown by pulsed laser deposition. We also demonstrate room-temperature conductive probe-based switching of quasi-one-dimensional structures. This work demonstrates that a scalable growth process can be used to create the two-dimensional electron gas system at oxidemore » heterointerfaces.« less