Phase coherent transport in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>SrTiO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mtext>LaAlO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>interfaces

Rakhmilevitch, D.; Shalom, M. Ben; Eshkol, M.; Tsukernik, A.; Palevski, A.; Dagan, Y.

doi:10.1103/physrevb.82.235119

Cited by 30 publications

(46 citation statements)

References 29 publications

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“…We have previously proposed that valley degeneracy of 3 is required to reconcile the root mean square amplitude and the width of the universal quantum fluctuations. [21] The three-fold valley degeneracy is consistent with SdH measurements on SrTiO 3 . [22] The valley degeneracy picture is probably oversimplified.…”

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confidence: 75%

Shubnikov–De Haas Oscillations inSrTiO3/LaAlO3Interface

et al. 2010

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Quantum magnetic oscillations in SrTiO3/LaAlO3 interface are observed. The evolution of their frequency and amplitude at various gate voltages and temperatures is studied. The data are consistent with the Shubnikov de-Haas theory. The Hall resistivity ρxy exhibits nonlinearity at low magnetic field. ρxy is fitted assuming multiple carrier contributions. The comparison between the mobile carrier density inferred from the Hall data and the oscillation frequency suggests multiple valley and spin degeneracy. The small amplitude of the oscillations is discussed in the framework of the multiple band scenario. PACS numbers: 75.70.Cn, The two dimensional electron gas (2DEG) formed at the interface between two insulating perovskites is a subject of intense scientific interest.[1] The most widely studied interface has been the one created between SrTiO 3 and LaAlO 3 .[2] At low temperatures this 2DEG has a superconducting ground state, whose critical temperature can be modified by an electric field effect.[3]The nature of the charge carriers and their origin are still a matter of debate. [4][5][6][7][8][9][10][11] The thickness of the conducting layer has been estimated to be of a few nanometers by both transport measurements [12][13] and by using a conducting atomic force microscope (AFM). [14] From the AFM data analysis Copie et al. conclude that two types of charge carriers screen the local electric fields. The magnetoresistance is strongly anisotropic [12] and effected by a gate dependent spin-orbit interaction. [15,16] The ρ xy is non linear in magnetic field, [15,17] and therefore it does not relate in a simple way to the number of charge carriers. The effective mass has been estimated using elipsometry[18] to be 2.2 m e with m e the electron mass. The number of charge carriers, their effective mass and the effect of gate voltage on their mobility are a subject of vigorous research.Quantum oscillations in magnetic fields have been extensively used to study the electronic properties of metals semiconductors and correlated systems. In the standard theory of Shubnikov-de Haas (SdH) the amplitude of the oscillating part of the resistance is [19]Where R c is the non-oscillating part of the resistance. The oscillation amplitude decays with temperature as given bywith m * the quasiparticle effective mass. The Dingle factor iswith ω c = eB m * and τ D the Dingle scattering time, which is related to the Dingle temperature by k B T D = /2πτ D . This factor determines the decay of the amplitude of the oscillations as the field decreases. Increasing the magnetic field, lowering the temperatures and decreasing the scattering rate should all lead to increasing oscillations amplitude.In this letter we report longitudinal and Hall resistance measurements at low temperatures and intense magnetic fields of up to 31.5 T. The high magnetic field enables us to detect quantum oscillations in the longitudinal resistivity, as well as nonlinearities in the Hall resistance. The data are consistent with the SdH theory, enabling us to extract ...

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confidence: 75%

Shubnikov–De Haas Oscillations inSrTiO3/LaAlO3Interface

et al. 2010

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“…For L ¼ l u , the amplitude of such fluctuations is expected to have the universal value e 2 =h. Estimations of l u in LAO/STO interfaces yield values in the range of 100-200 nm at 1.5 K. 7,20,32 Therefore, our small bridges are expected to display UCF at low temperatures, albeit with a reduced amplitude since their dimensions are still larger than l u . Figure 4(c) shows a magnetoconductance trace of the 500 nm wide device measured at 40 mK.…”

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“…For magnetic fields large enough to suppress superconductivity, magnetoresistance measurements display universal conductance fluctuations (UCFs). As UCF stem from phasecoherent transport, 5,7,20 their observation indicates that the devices fabricated with the technique described in this paper allow the mesoscopic transport regime to be accessed.…”

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In-plane electronic confinement in superconducting LaAlO3/SrTiO3 nanostructures

Stornaiuolo

Gariglio

Couto

et al. 2012

Applied Physics Letters

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Effect of Co-doping on the resistivity and thermopower of SmFe1-xCoxAsO (0.0≤x≤0.3) AIP Advances 2, 042137 (2012) Critical current reduction in coated conductors when in-plane fields are applied J. Appl. Phys. 112, 073918 (2012) Study of Bi2Sr2CaCu2O8/BiFeO3 nano-composite for electrical transport applications J. Appl. Phys. 112, 053916 (2012) Para-conductivity and critical regime of (Tl1−xCx)Ba2Ca3Cu4O12−δ superconductors J. Appl. Phys. 112, 033912 (2012) The electrical conductivity of bundles of superconducting nanowires produced by laser ablation of metals in superfluid helium

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“…Further increases of the spinorbit strength have been linked to quantum critical points in the system [14,15]. Universal conductance fluctuations (UCF) corresponding to phase coherence lengths of several microns have recently been observed in LAO/STO microstructures [16]. Recently, conductive atomic force microscope tips have been used to create nanoscale conduction paths at the LAO/STO interface [17,18].…”

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Universal conductance fluctuations in electrolyte-gated SrTiO3 nanostructures

Stanwyck¹,

Gallagher²,

Williams³

et al. 2013

Applied Physics Letters

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We report low-temperature magnetoconductance measurements of a patterned two-dimensional electron system (2DES) at the surface of strontium titanate, gated by an ionic liquid electrolyte. We observe universal conductance fluctuations, a signature of phase-coherent transport in mesoscopic devices. From the universal conductance fluctuations we extract an electron dephasing rate linear in temperature, characteristic of electron-electron interaction in a disordered conductor. Furthermore, the dephasing rate has a temperature-independent offset, suggestive of unscreened local magnetic moments in the sample.Strontium titanate (STO) has been the subject of a resurgence of experimental interest, mainly because of the recent ability to create STO-based materials with electrons confined in one and two spatial dimensions [1]. STO is also known to host a wide variety of electronic ground states determined by the density of electrons. These two aspects combine to create a promising system for studying nanoscale electronics where the interactions between electrons can be controlled simply by a gate voltage. Two-dimensional electron systems in STO have primarily been created in three different ways: growing a polar overlayer, usually lanthanum aluminate(LAO), to create a heterointerface[2], δ-doping with Nb or La [3,4], or with an electrolyte gate in an electric double-layer transistor (EDLT) configuration [5][6][7]. Low-temperature transport in these systems has revealed a wide variety of electronic ground states. Undoped STO is an insulator, but at ∼1x10 13 cm −2 the system becomes a metal. At higher densities (∼3x10 13 cm −2 ) -still much lower than typical BCS superconductors -the system becomes a two-dimensional superconductor. Early evidence suggests that the entrance into a superconducting state is a Berezinskii-KosterlitzThouless transition [8]. At even higher densities, a ferromagnetic phase appears to exist [9,10] and may even coexist with superconductivity [11][12][13].The handful of experiments on the quantum transport properties of two-dimensional electrons in STO have thus far focused on locally patterned LAO/STO, and have produced several interesting observations. The Rashba spin-orbit interaction -extracted from weak antilocalization measurements -is relatively large and tunable by application of a gate voltage. Further increases of the spinorbit strength have been linked to quantum critical points in the system [14,15]. Universal conductance fluctuations (UCF) corresponding to phase coherence lengths of several microns have recently been observed in LAO/STO microstructures [16]. Recently, conductive atomic force microscope tips have been used to create nanoscale conduction paths at the LAO/STO interface [17,18].In contrast, in electrolyte-gated STO some of the most basic properties of the quantum transport have yet to be investigated. In this work, we apply the EDLT technique to an undoped STO sample with nanopatterned metallic gates to study STO 2DESs with lateral confinement on the hundred-nanometer scale. ...

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Phase coherent transport inSrTiO3/LaAlO3interfaces

Cited by 30 publications

References 29 publications

Shubnikov–De Haas Oscillations inSrTiO3/LaAlO3Interface

Shubnikov–De Haas Oscillations inSrTiO3/LaAlO3Interface

In-plane electronic confinement in superconducting LaAlO3/SrTiO3 nanostructures

Universal conductance fluctuations in electrolyte-gated SrTiO3 nanostructures

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