Mechanical Tuning of LaAlO<sub>3</sub>/SrTiO<sub>3</sub> Interface Conductivity

Sharma, Pankaj; Ryu, Sangwoo; Burton, John; Paudel, Tula R.; Bark, Chung Wung; Huang, Zhen; Ariando, Ariando; Tsymbal, Evgeny Y.; Catalán, Gustau; Eom, C. B.; Gruverman, Alexei

doi:10.1021/acs.nanolett.5b01021

Cited by 80 publications

(80 citation statements)

References 38 publications

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“…S5). Using smaller tips and stronger forces it should be possible to reach the irreversible regime 29 . For calculating the contact area (a) we used the Hertzian contact formula:…”

Section: Methodsmentioning

confidence: 99%

Imaging and tuning polarity at SrTiO3 domain walls

et al. 2017

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Electrostatic fields tune the ground state of interfaces between complex oxide materials. Electronic properties, such as conductivity and superconductivity, can be tuned and then used to create and control circuit elements and gate-defined devices. Here we show that naturally occurring twin boundaries, with properties that are different from their surrounding bulk, can tune the LaAlO/SrTiO interface 2DEG at the nanoscale. In particular, SrTiO domain boundaries have the unusual distinction of remaining highly mobile down to low temperatures, and were recently suggested to be polar. Here we apply localized pressure to an individual SrTiO twin boundary and detect a change in LaAlO/SrTiO interface current distribution. Our data directly confirm the existence of polarity at the twin boundaries, and demonstrate that they can serve as effective tunable gates. As the location of SrTiO domain walls can be controlled using external field stimuli, our findings suggest a novel approach to manipulate SrTiO-based devices on the nanoscale.

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“…S5). Using smaller tips and stronger forces it should be possible to reach the irreversible regime 29 . For calculating the contact area (a) we used the Hertzian contact formula:…”

Section: Methodsmentioning

confidence: 99%

Imaging and tuning polarity at SrTiO3 domain walls

et al. 2017

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“…mechanically assisted resistive switching. 33 Further experiments to determine the kinetics of this effect, as well as the influence of surface termination (effectiveness of the electric field through SrO terminated with respect to TiO 2 terminated films 34 ) are underway.…”

Section: Methodsmentioning

confidence: 99%

Oxygen vacancies in strained SrTiO3 thin films: Formation enthalpy and manipulation

et al. 2017

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We report the enthalpy of oxygen vacancy formation in thin films of electron-doped SrTiO3, under different degrees of epitaxial stress. We demonstrate that both compressive and tensile strain decrease this energy at a very similar rate, and promote the formation of stable doubly ionized oxygen vacancies. Moreover, we also show that unintentional cationic vacancies introduced under typical growth conditions, produce a characteristic rotation pattern of TiO6 octahedra. The local concentration of oxygen vacancies can be modulated by an electric field with an AFM tip, changing not only the local electrical potential, but also producing a non-volatile mechanical response whose sign (up/down) can be reversed by the electric field.

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“…A characteristic of ferroelectric materials is that mechanical strain may also alter the polarization and thus switch the piezoresponse of the material. To test this, Sharma et al [363] used a grounded AFM tip to apply mechanical strain to a LaAlO 3 /SrTiO 3 heterostructure. With increasing force, it was found that the resistance of the interface could be switched from a high to a low value (Figure 4.3 c).…”

Section: Ferroelectric and Piezoelectric Propertiesmentioning

confidence: 99%

Physics of SrTiO₃-based heterostructures and nanostructures: a review

et al. 2018

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1 Overview 1 1.1 Introduction 1 1.1.1 Oxide growth techniques are rooted in search for high-Tc superconductors 2 1.1.2 First reports of interface conductivity 2 1.2 2D physics 2 1.3 Emergent properties of oxide heterostructures and nanostructures 3 1.4 Outline 3 2 Relevant properties of SrTiO3 3 2.1 Structural properties and transitions 3 2.2 Ferroelectricity, Paraelectricity and Quantum Paraelectricity 4 2.3 Electronic structure 5 2.4 Defects 6 2.4.1 Oxygen vacancies 6 2.4.2 Terraces 7 2.5 Superconductivity 7 3 SrTiO3-based heterostructures and nanostructures 8 3.1 Varieties of heterostructures 8 3.1.1 SrTiO3 only 9 3.1.2 LaAlO3/SrTiO3 9 3.1.3 Other heterostructures formed with SrTiO3 10 3.2 Thin-film growth 10 3.2.1 Substrates 10 3.2.2 SrTiO3 surface treatment 11 3.2.3 Pulsed Laser Deposition 11 3.2.4 Atomic Layer Deposition 13 3.2.5 Molecular Beam Epitaxy 14 3.2.6 Sputtering 15 3.3 Device Fabrication 15 3.3.1 "Conventional" photolithography - Thickness Modulation, hard masks, etc. 15 3.3.2 Ion beam irradiation 16 3.3.3 Conductive-AFM lithography 16 4 Properties and phase diagram of LaAlO3/SrTiO3 16 4.1 Insulating state 16 4.2 Conducting state 17 4.2.1 Confinement thickness (the depth profile of the 2DEG) 17 4.3 Metal-insulator transition and critical thickness 18 4.3.1 Polar catastrophe ( electronic reconstruction) 18 4.3.2 Oxygen Vacancies 19 4.3.3 Interdiffusion 20 4.3.4 Polar Interdiffusion + oxygen vacancies + antisite pairs 20 4.3.5 Role of surface adsorbates 21 4.3.6 Hidden FE like distortion - Strain induced instability 21 4.4 Structural properties and transitions 21 4.5 Electronic band structure 22 4.5.1 Theory 22 4.5.2 Experiment 23 4.5.3 Lifshitz transition 24 4.6 Defects, doping, and compensation 25 4.7 Magnetism 25 4.7.1 Experimental evidence 25 4.7.2 Two types of magnetism 27 4.7.3 Ferromagnetism 27 4.7.4 Metamagnetism 28 4.8 Superconductivity 28 4.9 Optical properties 29 4.9.1 Photoluminesce experiments 29 4.9.2 Second Harmonic Generation 29 4.10 Coexistence of superconductivity and magnetism 30 4.11 Magnetic and conducting phases 30 5 Quantum transport in LaAlO3/SrTiO3 heterostructures and microstructures 31 5.1 2D transport 31 5.2 Inhomogeneous Transport 31 5.3 Anisotropic Magnetoresistance 32 5.4 Spin-orbit coupling 32 5.5 Anomalous Hall Effect 34 5.6 Shubnikov-de Haas (SdH) Oscillation 35 5.7 Quantum Hall Effect 37 5.8 Spintronic Effects 38 6 Quantum transport in LaAlO3/SrTiO3 nanostructures 39 6.1 Quasi-1D Superconductivity 39 6.2 Universal conductance fluctuations 40 6.3 Dissipationless Electronic Waveguides 40 6.4 Superconducting Quantum Interference Devices (SQUID) 41 6.5 Electron pairing without superconductivity 41 6.6 Tun...

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Mechanical Tuning of LaAlO₃/SrTiO₃ Interface Conductivity

Cited by 80 publications

References 38 publications

Imaging and tuning polarity at SrTiO3 domain walls

Imaging and tuning polarity at SrTiO3 domain walls

Oxygen vacancies in strained SrTiO3 thin films: Formation enthalpy and manipulation

Physics of SrTiO₃-based heterostructures and nanostructures: a review

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Mechanical Tuning of LaAlO3/SrTiO3 Interface Conductivity

Cited by 80 publications

References 38 publications

Imaging and tuning polarity at SrTiO3 domain walls

Imaging and tuning polarity at SrTiO3 domain walls

Oxygen vacancies in strained SrTiO3 thin films: Formation enthalpy and manipulation

Physics of SrTiO3-based heterostructures and nanostructures: a review

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Product

Resources

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Mechanical Tuning of LaAlO₃/SrTiO₃ Interface Conductivity

Physics of SrTiO₃-based heterostructures and nanostructures: a review