In-plane electronic confinement in superconducting LaAlO3/SrTiO3 nanostructures

Stornaiuolo, Daniela; Gariglio, Stefano; Couto, Nuno J. G.; Fête, Alexandre; Caviglia, Andrea D.; Seyfarth, Gabriel; Jaccard, D.; Morpurgo, Alberto F.; Triscone, Jean‐Marc

doi:10.1063/1.4768936

Cited by 68 publications

(86 citation statements)

References 29 publications

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“…The patterned 2DEG exhibits a critical thickness of 2 unit cells -Al2O3 for the occurrence of interface conductivity, similar to the unpatterned sample. However, its maximum carrier density is found to be approximately 3×10 13 cm -2 , much lower than that of the unpatterned sample (~10 15 cm -2 ). Remarkably, a high electron mobility of approximately 3,600 cm 2 V -1 s -1 was obtained at low temperatures for the patterned 2DEG at a carrier density of ~ 7×10 12 cm -2 , which exhibits clear Shubnikov-de Hass quantum oscillations.…”

Section: Introductionmentioning

confidence: 92%

“…Although nano-patterned interfaces by conducting-atomic force microscopy (c-AFM) 11 have been demonstrated, micro-patterning of complex oxides has been proven to be challenging. This so far has been implemented primarily using amorphous LaAlO3-or AlOx-hard masks [12][13][14][15] or Ar-ion beam irradiation 16 . These processes, generally, require additional care as the deposition of amorphous LAO or AlOx layers or the Ar-ion irradiation can by itself induce conductivity in STO, 7,17,18 leading to failure of the patterned devices.…”

Section: Introductionmentioning

confidence: 99%

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Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

Niu

Gan

Zhang

et al. 2017

Applied Physics Letters

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The two-dimensional electron gas (2DEG) at the non-isostructural interface between spinel γ-Al2O3 and perovskite SrTiO3 is featured by a record electron mobility among complex oxide interfaces in addition to a high carrier density up to the order of 1015 cm−2. Herein, we report on the patterning of 2DEG at the γ-Al2O3/SrTiO3 interface grown at 650 °C by pulsed laser deposition using a hard mask of LaMnO3. The patterned 2DEG exhibits a critical thickness of 2 unit cells of γ-Al2O3 for the occurrence of interface conductivity, similar to the unpatterned sample. However, its maximum carrier density is found to be approximately 3 × 1013 cm−2, much lower than that of the unpatterned sample (∼1015 cm−2). Remarkably, a high electron mobility of approximately 3600 cm2 V−1 s−1 was obtained at low temperatures for the patterned 2DEG at a carrier density of ∼7 × 1012 cm−2, which exhibits clear Shubnikov-de Haas quantum oscillations. The patterned high-mobility 2DEG at the γ-Al2O3/SrTiO3 interface paves the way for the design and application of spinel/perovskite interfaces for high-mobility all-oxide electronic devices.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

Niu

Gan

Zhang

et al. 2017

Applied Physics Letters

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“…For attractive short range interactions, 2K ¼ 1=K and K < 1 can be realized by fermions (spin full in this example) with long range repulsive or attractive interactions allowing for the interesting regime K < 1. This case could potentially be realized with the new superconducting LaAlO 3 =SrTiO 3 nanostructures [42].…”

mentioning

confidence: 99%

Phase Transitions for a Collective Coordinate Coupled to Luttinger Liquids

2013

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We study various realizations of collective coordinates, e.g., the position of a particle, the charge of a Coulomb box, or the phase of a Bose or a superconducting condensate, coupled to Luttinger liquids with N flavors. We find that for a Luttinger parameter ð1=2Þ < K < 1 there is a phase transition from a delocalized phase into a phase with a periodic potential at strong coupling. In the delocalized phase the dynamics is dominated by an effective mass, i.e., diffusive in imaginary time, while on the transition line it becomes dissipative. At K ¼ ð1=2Þ there is an additional transition into a localized phase with no diffusion at zero temperature.

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“…Furthermore, nanoscale lateral control of carriers could allow fabrication of gate-tunable, single-material Josephson junctions and superconducting quantum interference devices, as well as mesoscopic devices. However, few experiments on nanostructures in STO systems exist: superconductivity has been demonstrated in submicron regions tunable with a global back gate 22 , and channels sketched by a nanoscale tip show superconducting features 23 . In this work, we demonstrate the first realization of an all-STO, gate-tunable superconducting weak link.…”

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confidence: 99%

Gate-tunable superconducting weak link and quantum point contact spectroscopy on a strontium titanate surface

et al. 2014

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Two-dimensional electron systems in gallium arsenide and graphene have enabled ground-breaking discoveries in condensed-matter physics, in part because they are easily modulated by voltages on nanopatterned gate electrodes. Electron systems at oxide interfaces hold a similarly large potential for fundamental studies of correlated electrons and novel device technologies 1-3 , but typically have carrier densities too large to control by conventional gating techniques. Here we present a quantum transport study of a superconducting strontium titanate (STO) interface, enabled by a combination of electrolyte 4-7 and metal-oxide gating. Our structure consists of two superconducting STO banks flanking a nanoscale STO weak link, which is tunable at low temperatures from insulating to superconducting behaviour by a local metallic gate. At low gate voltages, our device behaves as a quantum point contact that exhibits a minimum conductance plateau of e 2 /h in zero applied magnetic field, half the expected value for spin-degenerate electrons, but consistent with predictions 8-12 and experimental signatures 13-18 of a magnetically ordered ground state. The quantum point contact mediates tunnelling between normal and superconducting regions, enabling lateral tunnelling spectroscopy of the local superconducting state. Our work provides a generic scheme for quantum transport studies of STO and other surface electron liquids.Transition metal oxides exhibit electronic ground states not seen in conventional semiconductors 2,3 . For instance, the interface between lanthanum aluminate and strontium titanate 19 -two non-magnetic band insulators-hosts superconductivity 20 and magnetism [13][14][15][16][17][18] . Rashba spin-orbit coupling at conductive STO interfaces 21 has led to predictions of unconventional superconducting states 10 , and of helical wires and Majorana fermions in nanoscale STO channels 11 . Furthermore, nanoscale lateral control of carriers could allow fabrication of gate-tunable, single-material Josephson junctions and superconducting quantum interference devices, as well as mesoscopic devices. However, few experiments on nanostructures in STO systems exist: superconductivity has been demonstrated in submicron regions tunable with a global back gate 22 , and channels sketched by a nanoscale tip show superconducting features 23 . In this work, we demonstrate the first realization of an all-STO, gate-tunable superconducting weak link. We tune our device to the ballistic 1D limit and perform superconducting spectroscopy that agrees with BCS weak-coupling expectations and previous work 24 .Undoped STO is a band insulator. Inducing a two-dimensional (2D) electron density near 10 13 cm −2 creates a metal, and several times that density creates an optimally doped superconducting state 4 . To modulate the density on this scale, we use the electric double-layer transistor technique [4][5][6][7] . A schematic of our sample is shown in Fig. 1a. A single crystal of TiO 2 -terminated (100) SrTiO 3 is patterned with ohmic conta...

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In-plane electronic confinement in superconducting LaAlO3/SrTiO3 nanostructures

Cited by 68 publications

References 29 publications

Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

Phase Transitions for a Collective Coordinate Coupled to Luttinger Liquids

Gate-tunable superconducting weak link and quantum point contact spectroscopy on a strontium titanate surface

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