Gate-tuned superfluid density at the superconducting LaAlO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>/SrTiO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>interface

Bert, Julie A.; Nowack, Katja C.; Kalisky, Beena; Noad, Hilary; Kirtley, J. R.; Bell, Chris; Sato, Hiroki; Hosoda, Masayuki; Hikita, Y.; Hwang, Harold Y.; Moler, Kathryn A.

doi:10.1103/physrevb.86.060503

Cited by 114 publications

(156 citation statements)

References 32 publications

(36 reference statements)

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“…Scanning SQUID experiments yield a very low value of the superfluid density in this system [57,58]. Although no comparison has been made with bulk doped STO, a tempting explanation for these low values is that only d xz /d yz heavy electrons (that appear at the underdoped end-point of the dome) pair thus naturally explaining that the superfluid density is low, most of the interfacial carriers being xy in character and not participating to the superfluid density.…”

Section: Bulk and Interface Superconductivitymentioning

confidence: 99%

Interface superconductivity

Gariglio

Gabay

Mannhart

et al. 2015

Physica C: Superconductivity and its Applications

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Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO 3 and SrTiO 3 .We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO 3 and the interface system and the possible role of the interfacially induced Rashba type spin-orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high T c in a monolayer of FeSe deposited on SrTiO 3 .

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Section: Bulk and Interface Superconductivitymentioning

confidence: 99%

Interface superconductivity

Gariglio

Gabay

Mannhart

et al. 2015

Physica C: Superconductivity and its Applications

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“…Note that this scenario would naturally explain the low superfluid density (as compared to the total mobile carrier density) observed in scanning SQUID experiments. 65 One should bear in mind the fact that we use here the superconducting thickness obtained from critical field measurements. Establishing a direct connection between this thickness, the 3D carrier density profile and the extension of the different sub-bands is far from obvious but the issue is important and definitely deserves further attention.…”

Section: Superconductivitymentioning

confidence: 99%

Research Update: Conductivity and beyond at the LaAlO3/SrTiO3 interface

2016

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In this review, we focus on the celebrated interface between two band insulators, LaAlO3 and SrTiO3, that was found to be conducting, superconducting, and to display a strong spin-orbit coupling. We discuss the formation of the 2-dimensional electron liquid at this interface, the particular electronic structure linked to the carrier confinement, the transport properties, and the signatures of magnetism. We then highlight distinctive characteristics of the superconducting regime, such as the electric field effect control of the carrier density, the unique tunability observed in this system, and the role of the electronic subband structure. Finally we compare the behavior of Tc versus 2D doping with the dome-like behavior of the 3D bulk superconductivity observed in doped SrTiO3. This comparison reveals surprising differences when the Tc behavior is analyzed in terms of the 3D carrier density for the interface and the bulk.

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“…Here the electrostatic potential confining the electron gas at the interface is calculated self-consistently, finding that the electron confinement at the interface may induce phase separation, to avoid a thermodynamically unstable state with a negative compressibility. This provides a generic robust and intrinsic mechanism for the experimentally observed inhomogeneous character of these interfaces.PACS numbers: 73.43.Nq,73.21.Fg, The two-dimensional electron gas (2DEG) that forms at the interface of two insulating oxides, like LaAlO 3 /SrTiO 3 and LaTiO 3 /SrTiO 3 (hereafter generically referred to as LXO/STO) [1][2][3][4], exhibits a rich phenomenology, such as a gate-tunable metal-tosuperconductor transition [5][6][7][8], a magnetic-field-tuned quantum criticality [9], and inhomogeneous magnetic responses [10][11][12][13][14][15]. Tunneling [16,17] and SQUID magnetometry [18] provide clear evidence of an inhomogeneous interface on both micro-and nanoscopic scales.…”

mentioning

confidence: 99%

Phase Separation from Electron Confinement at Oxide Interfaces

et al. 2016

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Oxide heterostructures are of great interest both for fundamental and applicative reasons. In particular the two-dimensional electron gas at the LaAlO3/SrTiO3 or LaTiO3/SrTiO3 interfaces displays many different physical properties and functionalities. However there are clear indications that the interface electronic state is strongly inhomogeneous and therefore it is crucially relevant to investigate possible intrinsic electronic mechanisms underlying this inhomogeneity. Here the electrostatic potential confining the electron gas at the interface is calculated self-consistently, finding that the electron confinement at the interface may induce phase separation, to avoid a thermodynamically unstable state with a negative compressibility. This provides a generic robust and intrinsic mechanism for the experimentally observed inhomogeneous character of these interfaces.PACS numbers: 73.43.Nq,73.21.Fg, The two-dimensional electron gas (2DEG) that forms at the interface of two insulating oxides, like LaAlO 3 /SrTiO 3 and LaTiO 3 /SrTiO 3 (hereafter generically referred to as LXO/STO) [1][2][3][4], exhibits a rich phenomenology, such as a gate-tunable metal-tosuperconductor transition [5][6][7][8], a magnetic-field-tuned quantum criticality [9], and inhomogeneous magnetic responses [10][11][12][13][14][15]. Tunneling [16,17] and SQUID magnetometry [18] provide clear evidence of an inhomogeneous interface on both micro-and nanoscopic scales. Transport measurements report further signs of inhomogeneity and a percolative metal-to-superconductor transition with a sizable fraction of the 2DEG never becoming superconducting down to the lowest accessible temperatures [19][20][21][22]. For both fundamental reasons and applicative purposes, like device design, it is crucial to identify possible intrinsic mechanisms that may render the 2DEG so strongly inhomogeneous via a phase separation (PS). This is precisely the focus of the present work.Here, we identify a very effective electron-driven mechanism leading to PS, based on the confinement of the 2DEG at the interface. From customary self-consistent calculations of the confining potential well in semiconductors, it is well known [23] that a finite lateral extension usually renders the 2DEG more compressible than its strictly 2D counterpart. This effect is much stronger in LXO/STO than in ordinary semiconductor interfaces, due to the huge dielectric constant of STO, allowing for much larger electron densities, with a strong amplification of the self-consistent adjustments of the confining potential. As a consequence, a non-rigid band structure arises, which varies with the local electron density: an increased electron density is accompanied by a corresponding increase of the positive countercharges (due to oxygen vacancies and/or polarity catastrophe [24][25][26][27][28][29]), from which the interfacial electrons are introduced and restoring the overall charge neutrality. For small-to-moderate increases of electron and countercharge densities the potential well deepens and the e...

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Gate-tuned superfluid density at the superconducting LaAlO3/SrTiO3interface

Cited by 114 publications

References 32 publications

Interface superconductivity

Interface superconductivity

Research Update: Conductivity and beyond at the LaAlO3/SrTiO3 interface

Phase Separation from Electron Confinement at Oxide Interfaces

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