Hydrostatic pressure response of an oxide-based two-dimensional electron system

Zabaleta, Jone; Borisov, Vladislav; Wanke, R.; Jeschke, Harald O.; Parks, S.; Baum, B.; Teker, Ali; Harada, T.; Syassen, K.; Kopp, Thilo; Pavlenko, N. V.; Valentí, Roser; Mannhart, J.

doi:10.1103/physrevb.93.235117

Cited by 16 publications

(31 citation statements)

References 54 publications

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“…It should be noted that La and Al composition is also measured with RBS. However, it is a known issue that Al has a smaller backscattering cross-section, and its signal was buried in strong background from Sr and Ti 23 , 31 , 32 , which makes it difficult to determine the exact content of Al. Nevertheless, from the relative peak intensity and fittings (see supplementary information), we found the La/Al ratios inferred from RBS do qualitatively agree with the nominal La/Al ratios determined from the shutter-open time.…”

Section: Experimental Methodsmentioning

confidence: 99%

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

Tsai

Guo

et al. 2017

Sci Rep

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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.

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Section: Experimental Methodsmentioning

confidence: 99%

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

Tsai

Guo

et al. 2017

Sci Rep

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“…The 3d states are approximated by the atomic orbitals with n=3 and l=2, which are used for evaluating the CF matrix: 19,21,36,37 For the spinel-perovskite environment, Fig. 3(b), we find that the CF energy levels are dramatically rearranged due to the proximity of positively charged Al cations, which can be either octahedrally or tetrahedrally coordinated by oxygen.…”

Section: Symmetry-breaking Origin Of the Band-order Anomalymentioning

confidence: 99%

Band-Order Anomaly at the γ-Al₂O₃/SrTiO₃ Interface Drives the Electron-Mobility Boost

et al. 2021

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Rich functionalities of transition-metal oxides and their interfaces bear an enormous technological potential. Its realization in practical devices requires, however, a significant improvement of yet relatively low electron mobility in oxide materials. Recently, a mobility boost of about two orders of magnitude has been demonstrated at the spinel/perovskite γ-Al 2 O 3 /SrTiO 3 interface compared to the paradigm perovskite/perovskite LaAlO 3 /SrTiO 3 . We explore the fundamental physics behind this phenomenon from direct measurements of the momentum-resolved electronic structure of this interface using resonant soft-X-ray angle-resolved photoemission. We find an anomaly in orbital ordering of the mobile electrons in γ-Al 2 O 3 /SrTiO 3 which depopulates electron states in the top STO layer. This rearrangement of the mobile electron system pushes the electron density away from the interface that reduces its overlap with the interfacial defects and weakens the electron-phonon interaction, both effects contributing to the mobility boost. A crystal-field analysis shows that the band order alters owing to the symmetry breaking between the spinel γ-Al 2 O 3 and perovskite SrTiO 3 . The band-order engineering exploiting the fundamental symmetry properties emerges as another route to boost the performance of oxide devices.

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“…Mechanical strain was also found to be highly effective in tuning especially the electron mobility and the carrier density . When mechanically straining La‐doped STO by approximately 0.3% using a three‐point bending device, the electron mobility at low temperatures was found to increase by 300% as shown in Figure .…”

Section: Stress and Strainmentioning

confidence: 93%

“…The population of electrons in these bands then reduces the average effective mass and suppresses interband scattering . The LAO/STO interface and field effect transistors made hereof were shown to exhibit an increase in the carrier density, decrease of the mobility, and change in the transistor behavior upon application of hydrostatic pressure …”

Section: Stress and Strainmentioning

confidence: 93%

Stimulating Oxide Heterostructures: A Review on Controlling SrTiO₃‐Based Heterointerfaces with External Stimuli

Christensen

Trier

Niu

et al. 2019

Adv Materials Inter

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Oxides are an exciting class of electronic materials which share key properties with conventional semiconductors, but also bring new intrinsic functionalities that are not used in most current electronics: superconductivity, ferro-, pyro-, and piezoelectricity, ferromagnetism, and multiferrocity. Among the large number of oxides, strontium titanate (SrTiO 3 , STO) has been the center of attention in numerous studies for more than half a century. STO both serves as a popular template for epitaxial growth of oxide thin films as well as by itself exhibiting an attractive palettes of properties, including Numerous of the greatest inventions in modern society, such as solar cells, display panels, and transistors, rely on a simple concept: An external stimulus is applied to a material and the response is then utilized. Oxides often exhibit a colorful palette of responses to external stimuli due to the close coupling between lattice, spin, orbital, and charge degrees of freedom. In particular, oxide heterostructures where oxide thin films are deposited on SrTiO 3 have proven to be a fertile playground for material scientists, and a vast amount of interesting theoretical and experimental studies showcase the wide tunabilities of these heterostructures when subjected to external stimuli. Here, the authors review how the properties of SrTiO 3 -based heterostructures can be changed by external stimuli using electric fields, magnetic fields, light, stress, particle bombardment, liquids, gases, and temperature. The application of a single stimulus or several stimuli combined often leads to unexpected changes in properties which can open up for designing new devices as well as expanding the boundaries of our understanding within fundamental science. Hall of Fame Article is a research scientist at the Technical University of Denmark, Department of Energy Conversion and Storage. He received his B.Sc. (2009) and M.Sc. (2012) in nanoscience from the University of Copenhagen, followed by his Ph.D. (2017) and postdoc (2018) from the Technical University of Denmark. His work is currently focused on the physics of oxide materials and oxide devices for information technology and energy harvesting, including oxide electronics, memristors, internet of things, and thermoelectricity. Felix Trier is a postdoctoral researcher at CNRS/Thales, University Paris-Saclay. He obtained his B.Sc. (2009) and M.Sc. (2012) in nanoscience from the University of Copenhagen. Then he earned his Ph.D. degree (2016) from the Technical University of Denmark. His current research is focused on fabrication and characterization of metallic oxide heterointerface devices for the study of the spin-charge interconversion in 2D Rashba systems. His work concerns the LaAlO 3 /SrTiO 3 heterointerface 2D metal and its electrostatic tunability.Nini Pryds is a Professor and head of the research section "Functional Oxides" at the Department of Energy Conversion and Storage, Technical University of Denmark (DTU), where he is leading a group of researchers working in the field...

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Hydrostatic pressure response of an oxide-based two-dimensional electron system

Cited by 16 publications

References 54 publications

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

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

Band-Order Anomaly at the γ-Al₂O₃/SrTiO₃ Interface Drives the Electron-Mobility Boost

Stimulating Oxide Heterostructures: A Review on Controlling SrTiO₃‐Based Heterointerfaces with External Stimuli

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Hydrostatic pressure response of an oxide-based two-dimensional electron system

Cited by 16 publications

References 54 publications

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

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

Band-Order Anomaly at the γ-Al2O3/SrTiO3 Interface Drives the Electron-Mobility Boost

Stimulating Oxide Heterostructures: A Review on Controlling SrTiO3‐Based Heterointerfaces with External Stimuli

Contact Info

Product

Resources

About

Band-Order Anomaly at the γ-Al₂O₃/SrTiO₃ Interface Drives the Electron-Mobility Boost

Stimulating Oxide Heterostructures: A Review on Controlling SrTiO₃‐Based Heterointerfaces with External Stimuli