1
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Telesio F, Carrega M, Cappelli G, Iorio A, Crippa A, Strambini E, Giazotto F, Serrano-Ruiz M, Peruzzini M, Heun S. Evidence of Josephson Coupling in a Few-Layer Black Phosphorus Planar Josephson Junction. ACS NANO 2022; 16:3538-3545. [PMID: 35099941 PMCID: PMC8945388 DOI: 10.1021/acsnano.1c09315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Setting up strong Josephson coupling in van der Waals materials in close proximity to superconductors offers several opportunities both to inspect fundamental physics and to develop cryogenic quantum technologies. Here we show evidence of Josephson coupling in a planar few-layer black phosphorus junction. The planar geometry allows us to probe the junction behavior by means of external gates, at different carrier concentrations. Clear signatures of Josephson coupling are demonstrated by measuring supercurrent flow through the junction at milli-Kelvin temperatures. Manifestation of a Fraunhofer pattern with a transverse magnetic field is also reported, confirming the Josephson coupling. These findings represent evidence of proximity Josephson coupling in a planar junction based on a van der Waals material beyond graphene and will expedite further studies, exploiting the peculiar properties of exfoliated black phosphorus thin flakes.
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Affiliation(s)
- Francesca Telesio
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | | | - Giulio Cappelli
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Andrea Iorio
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Alessandro Crippa
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Elia Strambini
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Francesco Giazotto
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | | | | | - Stefan Heun
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
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2
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Mikheev E, Rosen IT, Goldhaber-Gordon D. Quantized critical supercurrent in SrTiO 3-based quantum point contacts. SCIENCE ADVANCES 2021; 7:eabi6520. [PMID: 34597141 PMCID: PMC10938545 DOI: 10.1126/sciadv.abi6520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Superconductivity in SrTiO3 occurs at remarkably low carrier densities and therefore, unlike conventional superconductors, can be controlled by electrostatic gates. Here, we demonstrate nanoscale weak links connecting superconducting leads, all within a single material, SrTiO3. Ionic liquid gating accumulates carriers in the leads, and local electrostatic gates are tuned to open the weak link. These devices behave as superconducting quantum point contacts with a quantized critical supercurrent. This is a milestone toward establishing SrTiO3 as a single-material platform for mesoscopic superconducting transport experiments that also intrinsically contains the necessary ingredients to engineer topological superconductivity.
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Affiliation(s)
- Evgeny Mikheev
- Department of Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Ilan T. Rosen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - David Goldhaber-Gordon
- Department of Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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3
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Singh G, Lesne E, Winkler D, Claeson T, Bauch T, Lombardi F, Caviglia AD, Kalaboukhov A. Nanopatterning of Weak Links in Superconducting Oxide Interfaces. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:398. [PMID: 33557305 PMCID: PMC7914727 DOI: 10.3390/nano11020398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 11/16/2022]
Abstract
The interface between two wide band-gap insulators, LaAlO3 and SrTiO3 (LAO/STO), hosts a quasi-two-dimensional electron gas (q2DEG), two-dimensional superconductivity, ferromagnetism, and giant Rashba spin-orbit coupling. The co-existence of two-dimensional superconductivity with gate-tunable spin-orbit coupling and multiband occupation is of particular interest for the realization of unconventional superconducting pairing. To investigate the symmetry of the superconducting order parameter, phase sensitive measurements of the Josephson effect are required. We describe an approach for the fabrication of artificial superconducting weak links at the LAO/STO interface using direct high-resolution electron beam lithography and low-energy argon ion beam irradiation. The method does not require lift-off steps or sacrificial layers. Therefore, resolution is only limited by the electron beam lithography and pattern transfer. We have realized superconducting weak links with a barrier thickness of 30-100 nm. The barrier transparency of the weak links can be controlled by the irradiation dose and further tuned by a gate voltage. Our results open up new possibilities for the realization of quantum devices in oxide interfaces.
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Affiliation(s)
- Gyanendra Singh
- Department of Microtechnology and Nanoscience—MC2, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; (G.S.); (D.W.); (T.C.); (T.B.); (F.L.)
| | - Edouard Lesne
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands; (E.L.); (A.D.C.)
| | - Dag Winkler
- Department of Microtechnology and Nanoscience—MC2, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; (G.S.); (D.W.); (T.C.); (T.B.); (F.L.)
| | - Tord Claeson
- Department of Microtechnology and Nanoscience—MC2, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; (G.S.); (D.W.); (T.C.); (T.B.); (F.L.)
| | - Thilo Bauch
- Department of Microtechnology and Nanoscience—MC2, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; (G.S.); (D.W.); (T.C.); (T.B.); (F.L.)
| | - Floriana Lombardi
- Department of Microtechnology and Nanoscience—MC2, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; (G.S.); (D.W.); (T.C.); (T.B.); (F.L.)
| | - Andrea D. Caviglia
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands; (E.L.); (A.D.C.)
| | - Alexei Kalaboukhov
- Department of Microtechnology and Nanoscience—MC2, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; (G.S.); (D.W.); (T.C.); (T.B.); (F.L.)
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4
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Manca N, Bothner D, Monteiro AMRVL, Davidovikj D, Sağlam YG, Jenkins M, Gabay M, Steele GA, Caviglia AD. Bimodal Phase Diagram of the Superfluid Density in LaAlO_{3}/SrTiO_{3} Revealed by an Interfacial Waveguide Resonator. PHYSICAL REVIEW LETTERS 2019; 122:036801. [PMID: 30735404 DOI: 10.1103/physrevlett.122.036801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Indexed: 06/09/2023]
Abstract
We explore the superconducting phase diagram of the two-dimensional electron system at the LaAlO_{3}/SrTiO_{3} interface by monitoring the frequencies of the cavity modes of a coplanar waveguide resonator fabricated in the interface itself. We determine the phase diagram of the superconducting transition as a function of the temperature and electrostatic gating, finding that both the superfluid density and the transition temperature follow a dome shape but that the two are not monotonically related. The ground state of this two-dimensional electron system is interpreted as a Josephson junction array, where a transition from long- to short-range order occurs as a function of the electronic doping. The synergy between correlated oxides and superconducting circuits is revealed to be a promising route to investigate these exotic compounds, complementary to standard magnetotransport measurements.
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Affiliation(s)
- Nicola Manca
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Daniel Bothner
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Ana M R V L Monteiro
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Dejan Davidovikj
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Yildiz G Sağlam
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Mark Jenkins
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Marc Gabay
- Laboratoire de Physique des Solides, Universite Paris-Sud and CNRS, Batiment 510, 91450 Orsay, France
| | - Gary A Steele
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - Andrea D Caviglia
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
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5
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Han W, Cui F, Si Y, Mao X, Ding B, Kim H. Self-Assembly of Perovskite Crystals Anchored Al 2 O 3 -La 2 O 3 Nanofibrous Membranes with Robust Flexibility and Luminescence. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1801963. [PMID: 30204281 DOI: 10.1002/smll.201801963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/03/2018] [Indexed: 06/08/2023]
Abstract
Inorganic luminescent materials as one of the important high-performance materials are widely used for industry and scientific research, mainly owing to their outstanding luminescence properties. However, inorganic luminescent materials are typically brittle and inelastic, which greatly limit their use in practical applications, particularly in flexible optoelectronic devices. In this work, it is shown that "plum-pudding" like CsPbBr3 /Cs4 PbBr6 perovskite crystals anchor onto Al2 O3 -La2 O3 (CCAL) nanofibrous membranes, which are synthesized via a facile electrospinning and subsequent supersaturated recrystallization process. The as-synthesized CCAL membranes exhibit outstanding mechanical flexibility and luminescence properties. Meanwhile, the crystal structure and luminous performance of the CCAL membranes are regulated by different molar ratios of CsBr/PbBr2 . The photoluminescence reaches a maximum value for the CCAL membranes produced with a CsBr/PbBr2 ratio of 1, and shows a narrow emission line-width of 18 nm. Furthermore, the potential applications of the CCAL nanofibrous membranes in green light devices through a remote nanofibrous membranes packaging approach are demonstrated. A pure green emission is achieved with the Commission Internationale de L'Eclairage color coordinates of (0.28, 0.65). This facile strategy would open a new avenue to flexible inorganic luminescent materials for the lighting and backlight display industries.
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Affiliation(s)
- Weidong Han
- Department of BIN Convergence Technology, Chonbuk National University, Jeonju, 561-756, South Korea
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Fuhai Cui
- Department of BIN Convergence Technology, Chonbuk National University, Jeonju, 561-756, South Korea
| | - Yang Si
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Xue Mao
- School of Textile Science and Engineering, Xi'an Polytechnic University, Xi'an, 710048, China
| | - Bin Ding
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China
| | - Hakyong Kim
- Department of BIN Convergence Technology, Chonbuk National University, Jeonju, 561-756, South Korea
- Department of Organic Materials and Fiber Engineering, Chonbuk National University, Jeonju, 561-756, South Korea
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6
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Persky E, Kalisky B. Scanning SQUID View of Oxide Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706653. [PMID: 29718543 DOI: 10.1002/adma.201706653] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/18/2018] [Indexed: 06/08/2023]
Abstract
The emergence of states of matter in low-dimensional systems is one of the most intriguing topics in condensed matter physics. Interfaces between nonmagnetic, insulating oxides are found to give rise to surprising behaviors, such as metallic conductivity, superconductivity, and magnetism. Sensitive, noninvasive local characterization tools are essential for understanding the electronic and magnetic behavior of these systems. Here, the scanning superconducting quantum interference device (SQUID) technique for local magnetic imaging is described and its contribution to the field of oxide interfaces is reviewed.
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Affiliation(s)
- Eylon Persky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, 5290002,, Israel
| | - Beena Kalisky
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, 5290002,, Israel
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7
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Thierschmann H, Mulazimoglu E, Manca N, Goswami S, Klapwijk TM, Caviglia AD. Transport regimes of a split gate superconducting quantum point contact in the two-dimensional LaAlO 3/SrTiO 3 superfluid. Nat Commun 2018; 9:2276. [PMID: 29892080 PMCID: PMC5995834 DOI: 10.1038/s41467-018-04657-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 05/14/2018] [Indexed: 11/08/2022] Open
Abstract
One of the hallmark experiments of quantum transport is the observation of the quantized resistance in a point contact in GaAs/AlGaAs heterostructures. Being formed with split gate technology, these structures represent in an ideal manner equilibrium reservoirs which are connected only through a few electron mode channel. It has been a long standing goal to achieve similar experimental conditions also in superconductors. Here we demonstrate the formation of a superconducting quantum point contact (SQPC) with split gate technology in a two-dimensional superconductor, utilizing the unique gate tunability of the superfluid at the LaAlO3/SrTiO3 interface. When the constriction is tuned through the action of metallic split gates we identify three regimes of transport: First, SQPC for which the supercurrent is carried only by a few quantum transport channels. Second, superconducting island strongly coupled to the equilibrium reservoirs. Third, charge island with a discrete spectrum weakly coupled to the reservoirs.
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Affiliation(s)
- Holger Thierschmann
- Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands.
| | - Emre Mulazimoglu
- Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
| | - Nicola Manca
- Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
| | - Srijit Goswami
- Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
- QuTech, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
| | - Teun M Klapwijk
- Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
- Physics Department, Moscow State University of Education, Moscow, 119991, Russia
| | - Andrea D Caviglia
- Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands.
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8
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Pai YY, Lee H, Lee JW, Annadi A, Cheng G, Lu S, Tomczyk M, Huang M, Eom CB, Irvin P, Levy J. One-Dimensional Nature of Superconductivity at the LaAlO_{3}/SrTiO_{3} Interface. PHYSICAL REVIEW LETTERS 2018; 120:147001. [PMID: 29694119 DOI: 10.1103/physrevlett.120.147001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Indexed: 06/08/2023]
Abstract
We examine superconductivity in LaAlO_{3}/SrTiO_{3} channels with widths that transition from the 1D to the 2D regime. The superconducting critical current is independent of the channel width and increases approximately linearly with the number of parallel channels. Signatures of electron pairing outside of the superconducting regime are also found to be independent of the channel width. Collectively, these results indicate that superconductivity exists at the boundary of these channels and is absent within the interior region of the channels. The intrinsic 1D nature of superconductivity at the LaAlO_{3}/SrTiO_{3} interface imposes strong physical constraints on possible electron pairing mechanisms.
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Affiliation(s)
- Yun-Yi Pai
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Hyungwoo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Jung-Woo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Anil Annadi
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Guanglei Cheng
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Shicheng Lu
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Michelle Tomczyk
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Mengchen Huang
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Chang-Beom Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Patrick Irvin
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
| | - Jeremy Levy
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, Pennsylvania 15260, USA
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9
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Pai YY, Tylan-Tyler A, Irvin P, Levy J. Physics of SrTiO 3-based heterostructures and nanostructures: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:036503. [PMID: 29424362 DOI: 10.1088/1361-6633/aa892d] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This review provides a summary of the rich physics expressed within SrTiO3-based heterostructures and nanostructures. The intended audience is researchers who are working in the field of oxides, but also those with different backgrounds (e.g., semiconductor nanostructures). After reviewing the relevant properties of SrTiO3 itself, we will then discuss the basics of SrTiO3-based heterostructures, how they can be grown, and how devices are typically fabricated. Next, we will cover the physics of these heterostructures, including their phase diagram and coupling between the various degrees of freedom. Finally, we will review the rich landscape of quantum transport phenomena, as well as the devices that elicit them.
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Affiliation(s)
- Yun-Yi Pai
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, United States of America. Pittsburgh Quantum Institute, Pittsburgh, PA 15260, United States of America
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