1
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Hou Y, Nichele F, Chi H, Lodesani A, Wu Y, Ritter MF, Haxell DZ, Davydova M, Ilić S, Glezakou-Elbert O, Varambally A, Bergeret FS, Kamra A, Fu L, Lee PA, Moodera JS. Ubiquitous Superconducting Diode Effect in Superconductor Thin Films. PHYSICAL REVIEW LETTERS 2023; 131:027001. [PMID: 37505965 DOI: 10.1103/physrevlett.131.027001] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 05/09/2023] [Indexed: 07/30/2023]
Abstract
The macroscopic coherence in superconductors supports dissipationless supercurrents that could play a central role in emerging quantum technologies. Accomplishing unequal supercurrents in the forward and backward directions would enable unprecedented functionalities. This nonreciprocity of critical supercurrents is called the superconducting (SC) diode effect. We demonstrate the strong SC diode effect in conventional SC thin films, such as niobium and vanadium, employing external magnetic fields as small as 1 Oe. Interfacing the SC layer with a ferromagnetic semiconductor EuS, we further accomplish the nonvolatile SC diode effect reaching a giant efficiency of 65%. By careful control experiments and theoretical modeling, we demonstrate that the critical supercurrent nonreciprocity in SC thin films could be easily accomplished with asymmetrical vortex edge and surface barriers and the universal Meissner screening current governing the critical currents. Our engineering of the SC diode effect in simple systems opens the door for novel technologies while revealing the ubiquity of the Meissner screening effect induced SC diode effect in superconducting films, and it should be eliminated with great care in the search for exotic superconducting states harboring finite-momentum Cooper pairing.
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Affiliation(s)
- Yasen Hou
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Fabrizio Nichele
- IBM Research Europe - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Hang Chi
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- U.S. Army DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, USA
| | - Alessandro Lodesani
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yingying Wu
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Markus F Ritter
- IBM Research Europe - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Daniel Z Haxell
- IBM Research Europe - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Margarita Davydova
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Stefan Ilić
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Pº Manuel de Lardizabal 5, Donostia-San Sebastián 20018, Spain
| | | | | | - F Sebastian Bergeret
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Pº Manuel de Lardizabal 5, Donostia-San Sebastián 20018, Spain
- Donostia International Physics Center (DIPC), Donostia-San Sebastián 20018, Spain
| | - Akashdeep Kamra
- Condensed Matter Physics Center (IFIMAC) and Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Patrick A Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jagadeesh S Moodera
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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2
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Becerra VF, Trif M, Hyart T. Quantized Spin Pumping in Topological Ferromagnetic-Superconducting Nanowires. PHYSICAL REVIEW LETTERS 2023; 130:237002. [PMID: 37354416 DOI: 10.1103/physrevlett.130.237002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 04/20/2023] [Accepted: 05/16/2023] [Indexed: 06/26/2023]
Abstract
Semiconducting nanowires with strong spin-orbit coupling in the presence of induced superconductivity and ferromagnetism can support Majorana zero modes. We study the pumping due to the precession of the magnetization in single-subband nanowires and show that spin pumping is robustly quantized when the hybrid nanowire is in the topologically nontrivial phase, whereas charge pumping is not quantized. Moreover, there exists one-to-one correspondence between the quantized conductance, entropy change and spin pumping in long topologically nontrivial nanowires but these observables are uncorrelated in the case of accidental zero-energy Andreev bound states in the trivial phase. Thus, we conclude that observation of correlated and quantized peaks in the conductance, entropy change and spin pumping would provide strong evidence of Majorana zero modes, and we elaborate how topological Majorana zero modes can be distinguished from quasi-Majorana modes potentially created by a smooth tunnel barrier at the lead-nanowire interface. Finally, we discuss peculiar interference effects affecting the spin pumping in short nanowires at very low energies.
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Affiliation(s)
- V Fernández Becerra
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
| | - Mircea Trif
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
| | - Timo Hyart
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
- Department of Applied Physics, Aalto University, 00076 Aalto, Espoo, Finland
- Computational Physics Laboratory, Physics Unit, Faculty of Engineering and Natural Sciences, Tampere University, FI-33014 Tampere, Finland
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3
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Cayao J. Exceptional degeneracies in non-Hermitian Rashba semiconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:254002. [PMID: 37021876 DOI: 10.1088/1361-648x/acc7e9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
Exceptional points (EPs) are spectral degeneracies of non-Hermitian (NH) systems where eigenvalues and eigenvectors coalesce, inducing unique topological phases that have no counterpart in the Hermitian realm. Here we consider an NH system by coupling a two-dimensional semiconductor with Rashba spin-orbit coupling (SOC) to a ferromagnet lead and show the emergence of highly tunable EPs along rings in momentum space. Interestingly, these exceptional degeneracies are the endpoints of lines formed by the eigenvalue coalescence at finite real energy, resembling the bulk Fermi arcs commonly defined at zero real energy. We then show that an in-plane Zeeman field provides a way to control these exceptional degeneracies although higher values of non-Hermiticity are required in contrast to the zero Zeeman field regime. Furthermore, we find that the spin projections also coalescence at the exceptional degeneracies and can acquire larger values than in the Hermitian regime. Finally, we demonstrate that the exceptional degeneracies induce large spectral weights, which can be used as a signature for their detection. Our results thus reveal the potential of systems with Rashba SOC for realizing NH bulk phenomena.
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Affiliation(s)
- Jorge Cayao
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
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4
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Sub-nanometer mapping of strain-induced band structure variations in planar nanowire core-shell heterostructures. Nat Commun 2022; 13:4089. [PMID: 35835772 PMCID: PMC9283334 DOI: 10.1038/s41467-022-31778-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 07/01/2022] [Indexed: 11/22/2022] Open
Abstract
Strain relaxation mechanisms during epitaxial growth of core-shell nanostructures play a key role in determining their morphologies, crystal structure and properties. To unveil those mechanisms, we perform atomic-scale aberration-corrected scanning transmission electron microscopy studies on planar core-shell ZnSe@ZnTe nanowires on α-Al2O3 substrates. The core morphology affects the shell structure involving plane bending and the formation of low-angle polar boundaries. The origin of this phenomenon and its consequences on the electronic band structure are discussed. We further use monochromated valence electron energy-loss spectroscopy to obtain spatially resolved band-gap maps of the heterostructure with sub-nanometer spatial resolution. A decrease in band-gap energy at highly strained core-shell interfacial regions is found, along with a switch from direct to indirect band-gap. These findings represent an advance in the sub-nanometer-scale understanding of the interplay between structure and electronic properties associated with highly mismatched semiconductor heterostructures, especially with those related to the planar growth of heterostructured nanowire networks. Planar growth of nanowire arrays involves interactions between materials that affect the electronic behavior of the effective heterojunction. Here, authors show how core curvature and cross-section morphology affect shell growth, demonstrating how strain at the core-shell interface induces electronic band modulations in ZnSe@ZnTe nanowires.
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5
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Bobkova IV, Bobkov AM, Silaev MA. Magnetoelectric effects in Josephson junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:353001. [PMID: 35709718 DOI: 10.1088/1361-648x/ac7994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
The review is devoted to the fundamental aspects and characteristic features of the magnetoelectric effects, reported in the literature on Josephson junctions (JJs). The main focus of the review is on the manifestations of the direct and inverse magnetoelectric effects in various types of Josephson systems. They provide a coupling of the magnetization in superconductor/ferromagnet/superconductor JJs to the Josephson current. The direct magnetoelectric effect is a driving force of spin torques acting on the ferromagnet inside the JJ. Therefore it is of key importance for the electrical control of the magnetization. The inverse magnetoelectric effect accounts for the back action of the magnetization dynamics on the Josephson subsystem, in particular, making the JJ to be in the resistive state in the presence of the magnetization dynamics of any origin. The perspectives of the coupling of the magnetization in JJs with ferromagnetic interlayers to the Josephson current via the magnetoelectric effects are discussed.
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Affiliation(s)
- I V Bobkova
- Institute of Solid State Physics, Chernogolovka, Moscow Region 142432, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
- National Research University Higher School of Economics, Moscow 101000, Russia
| | - A M Bobkov
- Institute of Solid State Physics, Chernogolovka, Moscow Region 142432, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
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6
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Majorana Zero Modes in Ferromagnetic Wires without Spin-Orbit Coupling. CONDENSED MATTER 2021. [DOI: 10.3390/condmat6040044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We present a novel controllable platform for engineering Majorana zero modes. The platform consists of a ferromagnetic metallic wire placed among conventional superconductors, which are in proximity to ferromagnetic insulators. We demonstrate that Majorana zero modes emerge localised at the edges of the ferromagnetic wire, due to the interplay of the applied supercurrents and the induced by proximity exchange fields with conventional superconductivity. Our mechanism does not rely on the pairing of helical fermions by combining conventional superconductivity with spin-orbit coupling, but rather exploits the misalignment between the magnetization of the ferromagnetic insulators and that of the ferromagnetic wire.
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7
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Chatterjee S, Khalid S, Inbar HS, Goswami A, Guo T, Chang YH, Young E, Fedorov AV, Read D, Janotti A, Palmstrøm CJ. Controlling magnetoresistance by tuning semimetallicity through dimensional confinement and heteroepitaxy. SCIENCE ADVANCES 2021; 7:7/16/eabe8971. [PMID: 33853778 PMCID: PMC8046380 DOI: 10.1126/sciadv.abe8971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Controlling electronic properties via band structure engineering is at the heart of modern semiconductor devices. Here, we extend this concept to semimetals where, using LuSb as a model system, we show that quantum confinement lifts carrier compensation and differentially affects the mobility of the electron and hole-like carriers resulting in a strong modification in its large, nonsaturating magnetoresistance behavior. Bonding mismatch at the heteroepitaxial interface of a semimetal (LuSb) and a semiconductor (GaSb) leads to the emergence of a two-dimensional, interfacial hole gas. This is accompanied by a charge transfer across the interface that provides another avenue to modify the electronic structure and magnetotransport properties in the ultrathin limit. Our work lays out a general strategy of using confined thin-film geometries and heteroepitaxial interfaces to engineer electronic structure in semimetallic systems, which allows control over their magnetoresistance behavior and simultaneously provides insights into its origin.
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Affiliation(s)
- Shouvik Chatterjee
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA.
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Shoaib Khalid
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
| | - Hadass S Inbar
- Materials Department, University of California, Santa Barbara, CA 93106, USA
| | - Aranya Goswami
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA
| | - Taozhi Guo
- Department of Physics, University of California, Santa Barbara, CA 93106, USA
| | - Yu-Hao Chang
- Materials Department, University of California, Santa Barbara, CA 93106, USA
| | - Elliot Young
- Materials Department, University of California, Santa Barbara, CA 93106, USA
| | - Alexei V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Dan Read
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA
- School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, UK
| | - Anderson Janotti
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
| | - Chris J Palmstrøm
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA.
- Materials Department, University of California, Santa Barbara, CA 93106, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA 93106, USA
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8
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Jiang Y, de Jong EJ, van de Sande V, Gazibegovic S, Badawy G, Bakkers EPAM, Frolov SM. Hysteretic magnetoresistance in nanowire devices due to stray fields induced by micromagnets. NANOTECHNOLOGY 2021; 32:095001. [PMID: 33142271 DOI: 10.1088/1361-6528/abc70f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We study hysteretic magnetoresistance in InSb nanowires due to stray magnetic fields from CoFe micromagnets. Devices without any ferromagnetic components show that the magnetoresistance of InSb nanowires commonly exhibits either a local maximum or local minimum at zero magnetic field. Switching of microstrip magnetizations then results in positive or negative hysteretic dependence as conductance maxima or minima shift with respect to the global external field. Stray fields are found to be in the range of tens of millitesla, comparable to the scale over which the nanowire magnetoresistance develops. We observe that the stray field signal is similar to that obtained in devices with ferromagnetic contacts (spin valves). We perform micromagnetic simulations which are in reasonable agreement with the experiment. The use of locally varying magnetic fields may bring new ideas for Majorana circuits in which nanowire networks require control over field orientation at the nanoscale.
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Affiliation(s)
- Y Jiang
- University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | - E J de Jong
- Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - V van de Sande
- Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - S Gazibegovic
- Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - G Badawy
- Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - E P A M Bakkers
- Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - S M Frolov
- University of Pittsburgh, Pittsburgh, PA 15260, United States of America
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9
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Khan SA, Lampadaris C, Cui A, Stampfer L, Liu Y, Pauka SJ, Cachaza ME, Fiordaliso EM, Kang JH, Korneychuk S, Mutas T, Sestoft JE, Krizek F, Tanta R, Cassidy MC, Jespersen TS, Krogstrup P. Highly Transparent Gatable Superconducting Shadow Junctions. ACS NANO 2020; 14:14605-14615. [PMID: 32396328 DOI: 10.1021/acsnano.0c02979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gate-tunable junctions are key elements in quantum devices based on hybrid semiconductor-superconductor materials. They serve multiple purposes ranging from tunnel spectroscopy probes to voltage-controlled qubit operations in gatemon and topological qubits. Common to all is that junction transparency plays a critical role. In this study, we grow single-crystalline InAs, InSb, and InAs1-xSbx semiconductor nanowires with epitaxial Al, Sn, and Pb superconductors and in situ shadowed junctions in a single-step molecular beam epitaxy process. We investigate correlations between fabrication parameters, junction morphologies, and electronic transport properties of the junctions and show that the examined in situ shadowed junctions are of significantly higher quality than the etched junctions. By varying the edge sharpness of the shadow junctions, we show that the sharpest edges yield the highest junction transparency for all three examined semiconductors. Further, critical supercurrent measurements reveal an extraordinarily high ICRN, close to the KO-2 limit. This study demonstrates a promising engineering path toward reliable gate-tunable superconducting qubits.
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Affiliation(s)
- Sabbir A Khan
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Charalampos Lampadaris
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ajuan Cui
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Lukas Stampfer
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Yu Liu
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Sebastian J Pauka
- Microsoft Quantum Sydney, The University of Sydney, Sydney, NSW 2006, Australia
| | - Martin E Cachaza
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | - Jung-Hyun Kang
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Svetlana Korneychuk
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - Timo Mutas
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Joachim E Sestoft
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Filip Krizek
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Rawa Tanta
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Maja C Cassidy
- Microsoft Quantum Sydney, The University of Sydney, Sydney, NSW 2006, Australia
| | - Thomas S Jespersen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Peter Krogstrup
- Microsoft Quantum Materials Lab Copenhagen, 2800 Lyngby, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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10
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Strambini E, Iorio A, Durante O, Citro R, Sanz-Fernández C, Guarcello C, Tokatly IV, Braggio A, Rocci M, Ligato N, Zannier V, Sorba L, Bergeret FS, Giazotto F. A Josephson phase battery. NATURE NANOTECHNOLOGY 2020; 15:656-660. [PMID: 32541945 DOI: 10.1038/s41565-020-0712-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
A classical battery converts chemical energy into a persistent voltage bias that can power electronic circuits. Similarly, a phase battery is a quantum device that provides a persistent phase bias to the wave function of a quantum circuit. It represents a key element for quantum technologies based on phase coherence. Here we demonstrate a phase battery in a hybrid superconducting circuit. It consists of an n-doped InAs nanowire with unpaired-spin surface states, that is proximitized by Al superconducting leads. We find that the ferromagnetic polarization of the unpaired-spin states is efficiently converted into a persistent phase bias φ0 across the wire, leading to the anomalous Josephson effect1,2. We apply an external in-plane magnetic field and, thereby, achieve continuous tuning of φ0. Hence, we can charge and discharge the quantum phase battery. The observed symmetries of the anomalous Josephson effect in the vectorial magnetic field are in agreement with our theoretical model. Our results demonstrate how the combined action of spin-orbit coupling and exchange interaction induces a strong coupling between charge, spin and superconducting phase, able to break the phase rigidity of the system.
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Affiliation(s)
- Elia Strambini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
| | - Andrea Iorio
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
| | - Ofelia Durante
- Dipartimento di Fisica 'E. R. Caianiello', Università di Salerno, Fisciano, Italy
| | - Roberta Citro
- Dipartimento di Fisica 'E. R. Caianiello', Università di Salerno, Fisciano, Italy
| | | | - Claudio Guarcello
- Dipartimento di Fisica 'E. R. Caianiello', Università di Salerno, Fisciano, Italy
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, San Sebastián, Spain
| | - Ilya V Tokatly
- Nano-Bio Spectroscopy Group, Departamento de Física de Materiales, Universidad del País Vasco (UPV/EHU), Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Alessandro Braggio
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Mirko Rocci
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nadia Ligato
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Valentina Zannier
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Lucia Sorba
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - F Sebastián Bergeret
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, San Sebastián, Spain.
- Donostia International Physics Center (DIPC), San Sebastián, Spain.
| | - Francesco Giazotto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
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11
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Liu Y, Luchini A, Martí-Sánchez S, Koch C, Schuwalow S, Khan SA, Stankevič T, Francoual S, Mardegan JRL, Krieger JA, Strocov VN, Stahn J, Vaz CAF, Ramakrishnan M, Staub U, Lefmann K, Aeppli G, Arbiol J, Krogstrup P. Coherent Epitaxial Semiconductor-Ferromagnetic Insulator InAs/EuS Interfaces: Band Alignment and Magnetic Structure. ACS APPLIED MATERIALS & INTERFACES 2020; 12:8780-8787. [PMID: 31877013 DOI: 10.1021/acsami.9b15034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hybrid semiconductor-ferromagnetic insulator heterostructures are interesting due to their tunable electronic transport, self-sustained stray field, and local proximitized magnetic exchange. In this work, we present lattice-matched hybrid epitaxy of semiconductor-ferromagnetic insulator InAs/EuS heterostructures and analyze the atomic-scale structure and their electronic and magnetic characteristics. The Fermi level at the InAs/EuS interface is found to be close to the InAs conduction band and in the band gap of EuS, thus preserving the semiconducting properties. Both neutron and X-ray reflectivity measurements show that the overall ferromagnetic component is mainly localized in the EuS thin film with a suppression of the Eu moment in the EuS layer nearest the InAs and magnetic moments outside the detection limits on the pure InAs side. This work presents a step toward realizing defect-free semiconductor-ferromagnetic insulator epitaxial hybrids for spin-lifted quantum and spintronic applications without external magnetic fields.
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Affiliation(s)
- Yu Liu
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | | | - Sara Martí-Sánchez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Catalonia , Spain
| | - Christian Koch
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Catalonia , Spain
| | - Sergej Schuwalow
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | - Sabbir A Khan
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | - Tomaš Stankevič
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
| | - Sonia Francoual
- Deutsches Elektronen-Synchrotron DESY , Hamburg 22603 , Germany
| | | | | | | | - Jochen Stahn
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | - Carlos A F Vaz
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | | | - Urs Staub
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
| | | | - Gabriel Aeppli
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
- ETH , CH-8093 Zürich , Switzerland
- EPFL , CH-1015 Lausanne , Switzerland
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Catalonia , Spain
- ICREA , Pg. Lluís Companys 23 , 08010 Barcelona , Catalonia , Spain
| | - Peter Krogstrup
- Microsoft Quantum Materials Lab Copenhagen , 2800 Lyngby , Denmark
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