1
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Jardine MA, Dardzinski D, Yu M, Purkayastha A, Chen AH, Chang YH, Engel A, Strocov VN, Hocevar M, Palmstro̷m C, Frolov SM, Marom N. First-Principles Assessment of CdTe as a Tunnel Barrier at the α-Sn/InSb Interface. ACS Appl Mater Interfaces 2023; 15:16288-16298. [PMID: 36940162 PMCID: PMC10064317 DOI: 10.1021/acsami.3c00323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/09/2023] [Indexed: 06/17/2023]
Abstract
Majorana zero modes, with prospective applications in topological quantum computing, are expected to arise in superconductor/semiconductor interfaces, such as β-Sn and InSb. However, proximity to the superconductor may also adversely affect the semiconductor's local properties. A tunnel barrier inserted at the interface could resolve this issue. We assess the wide band gap semiconductor, CdTe, as a candidate material to mediate the coupling at the lattice-matched interface between α-Sn and InSb. To this end, we use density functional theory (DFT) with Hubbard U corrections, whose values are machine-learned via Bayesian optimization (BO) [ npj Computational Materials 2020, 6, 180]. The results of DFT+U(BO) are validated against angle resolved photoemission spectroscopy (ARPES) experiments for α-Sn and CdTe. For CdTe, the z-unfolding method [ Advanced Quantum Technologies 2022, 5, 2100033] is used to resolve the contributions of different kz values to the ARPES. We then study the band offsets and the penetration depth of metal-induced gap states (MIGS) in bilayer interfaces of InSb/α-Sn, InSb/CdTe, and CdTe/α-Sn, as well as in trilayer interfaces of InSb/CdTe/α-Sn with increasing thickness of CdTe. We find that 16 atomic layers (3.5 nm) of CdTe can serve as a tunnel barrier, effectively shielding the InSb from MIGS from the α-Sn. This may guide the choice of dimensions of the CdTe barrier to mediate the coupling in semiconductor-superconductor devices in future Majorana zero modes experiments.
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Affiliation(s)
- Malcolm
J. A. Jardine
- Department
of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Derek Dardzinski
- Department
of Materials Science and Engineering, Carnegie
Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Maituo Yu
- Department
of Materials Science and Engineering, Carnegie
Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Amrita Purkayastha
- Department
of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - An-Hsi Chen
- Department
of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Yu-Hao Chang
- Université
Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38000, France
| | - Aaron Engel
- Université
Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38000, France
| | - Vladimir N. Strocov
- Materials
Department, University of California-Santa
Barbara, Santa
Barbara, California 93106, United States
| | - Moïra Hocevar
- Department
of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Chris Palmstro̷m
- Université
Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble 38000, France
- Paul Scherrer
Institut, Swiss Light Source, Villigen PSI CH-5232, Switzerland
| | - Sergey M. Frolov
- Department
of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Noa Marom
- Department
of Materials Science and Engineering, Carnegie
Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Electrical and Computer Engineering, University of California-Santa Barbara, Santa Barbara, California 93106, United States
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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2
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Li CH, Moon J, van 't Erve OMJ, Wickramaratne D, Cobas ED, Johannes MD, Jonker BT. Spin-Sensitive Epitaxial In 2Se 3 Tunnel Barrier in In 2Se 3/Bi 2Se 3 Topological van der Waals Heterostructure. ACS Appl Mater Interfaces 2022; 14:34093-34100. [PMID: 35820066 DOI: 10.1021/acsami.2c08053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Current-generated spin arising from spin-momentum locking in topological insulator (TI) surface states has been shown to switch the magnetization of an adjacent ferromagnet (FM) via spin-orbit torque (SOT) with a much higher efficiency than heavy metals. However, in such FM/TI heterostructures, most of the current is shunted through the FM metal due to its lower resistance, and recent calculations have also shown that topological surface states can be significantly impacted when interfaced with an FM metal such as Ni and Co. Hence, placing an insulating layer between the TI and FM will not only prevent current shunting, therefore minimizing overall power consumption, but may also help preserve the topological surface states at the interface. Here, we report the van der Waals epitaxial growth of β-phase In2Se3 on Bi2Se3 by molecular beam epitaxy and demonstrate its spin sensitivity by the electrical detection of current-generated spin in Bi2Se3 surface states using a Fe/In2Se3 detector contact. Our density functional calculations further confirm that the linear dispersion and spin texture of the Bi2Se3 surface states are indeed preserved at the In2Se3/Bi2Se3 interface. This demonstration of an epitaxial crystalline spin-sensitive barrier that can be grown directly on Bi2Se3, and verification that it preserves the topological surface state, is electrically insulating and spin-sensitive, is an important step toward minimizing overall power consumption in SOT switching in TI/FM heterostructures in fully epitaxial topological spintronic devices.
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Affiliation(s)
- Connie H Li
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Jisoo Moon
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
- National Research Council, Washington, DC 20001, United States
| | - Olaf M J van 't Erve
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Darshana Wickramaratne
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Enrique D Cobas
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Michelle D Johannes
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Berend T Jonker
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
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3
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Büttner P, Scheler F, Pointer C, Döhler D, Yokosawa T, Spiecker E, Boix PP, Young ER, Mínguez-Bacho I, Bachmann J. ZnS Ultrathin Interfacial Layers for Optimizing Carrier Management in Sb 2S 3-based Photovoltaics. ACS Appl Mater Interfaces 2021; 13:11861-11868. [PMID: 33667064 PMCID: PMC7975279 DOI: 10.1021/acsami.0c21365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO2/Sb2S3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over the ZnS interlayer thickness on the ångström scale (0-1.5 nm) and to deposit highly pure Sb2S3. Our systematic study of the photovoltaic and optoelectronic properties of these devices by impedance spectroscopy and transient absorption concludes that the optimum ZnS interlayer thickness of 1.0 nm achieves the best balance between the beneficial effect of an increased recombination resistance at the interface and the deleterious barrier behavior of the wide-bandgap semiconductor ZnS. This optimization allows us to reach an overall power conversion efficiency of 5.09% in planar configuration.
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Affiliation(s)
- Pascal Büttner
- Friedrich-Alexander
University Erlangen-Nürnberg, Chemistry of Thin Film Materials, Department of Chemistry and Pharmacy,
IZNF, Cauerstraße
3, 91058 Erlangen, Germany
| | - Florian Scheler
- Friedrich-Alexander
University Erlangen-Nürnberg, Chemistry of Thin Film Materials, Department of Chemistry and Pharmacy,
IZNF, Cauerstraße
3, 91058 Erlangen, Germany
- Universidad
de Valencia, Instituto de Ciencia de Materiales, Catedrático J. Beltrán
2, 46980 Paterna, Spain
| | - Craig Pointer
- Lehigh
University, Department of Chemistry, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Dirk Döhler
- Friedrich-Alexander
University Erlangen-Nürnberg, Chemistry of Thin Film Materials, Department of Chemistry and Pharmacy,
IZNF, Cauerstraße
3, 91058 Erlangen, Germany
| | - Tadahiro Yokosawa
- Friedrich-Alexander
University Erlangen-Nürnberg, Institute
of Micro- and Nanostructure Research, and Center for Nanoanalysis
and Electron Microscopy (CENEM), IZNF, Cauerstraße 3, Erlangen, 91058 Germany
| | - Erdmann Spiecker
- Friedrich-Alexander
University Erlangen-Nürnberg, Institute
of Micro- and Nanostructure Research, and Center for Nanoanalysis
and Electron Microscopy (CENEM), IZNF, Cauerstraße 3, Erlangen, 91058 Germany
| | - Pablo P. Boix
- Universidad
de Valencia, Instituto de Ciencia de Materiales, Catedrático J. Beltrán
2, 46980 Paterna, Spain
| | - Elizabeth R. Young
- Lehigh
University, Department of Chemistry, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Ignacio Mínguez-Bacho
- Friedrich-Alexander
University Erlangen-Nürnberg, Chemistry of Thin Film Materials, Department of Chemistry and Pharmacy,
IZNF, Cauerstraße
3, 91058 Erlangen, Germany
| | - Julien Bachmann
- Friedrich-Alexander
University Erlangen-Nürnberg, Chemistry of Thin Film Materials, Department of Chemistry and Pharmacy,
IZNF, Cauerstraße
3, 91058 Erlangen, Germany
- Saint-Petersburg
State University, Institute of Chemistry, Universitetskii Prospekt 26, 198504 Saint Petersburg, Russia
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4
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Sadre Momtaz Z, Servino S, Demontis V, Zannier V, Ercolani D, Rossi F, Rossella F, Sorba L, Beltram F, Roddaro S. Orbital Tuning of Tunnel Coupling in InAs/InP Nanowire Quantum Dots. Nano Lett 2020; 20:1693-1699. [PMID: 32048854 PMCID: PMC7997631 DOI: 10.1021/acs.nanolett.9b04850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We report results on the control of barrier transparency in InAs/InP nanowire quantum dots via the electrostatic control of the device electron states. Recent works demonstrated that barrier transparency in this class of devices displays a general trend just depending on the total orbital energy of the trapped electrons. We show that a qualitatively different regime is observed at relatively low filling numbers, where tunneling rates are rather controlled by the axial configuration of the electron orbital. Transmission rates versus filling are further modified by acting on the radial configuration of the orbitals by means of electrostatic gating, and the barrier transparency for the various orbitals is found to evolve as expected from numerical simulations. The possibility to exploit this mechanism to achieve a controlled continuous tuning of the tunneling rate of an individual Coulomb blockade resonance is discussed.
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Affiliation(s)
- Zahra Sadre Momtaz
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
- E-mail:
| | - Stefano Servino
- Department
of Physics “E.Fermi”, Università
di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
| | - Valeria Demontis
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Valentina Zannier
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Daniele Ercolani
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Francesca Rossi
- IMEM-CNR
Institute, Parco Area delle Scienze, I-43124 Parma, Italy
| | - Francesco Rossella
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Lucia Sorba
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Fabio Beltram
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Stefano Roddaro
- NEST, Instituto Nanoscienze CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
- Department
of Physics “E.Fermi”, Università
di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
- E-mail:
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5
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Lee KH, Chakram S, Kim SE, Mujid F, Ray A, Gao H, Park C, Zhong Y, Muller DA, Schuster DI, Park J. Two-Dimensional Material Tunnel Barrier for Josephson Junctions and Superconducting Qubits. Nano Lett 2019; 19:8287-8293. [PMID: 31661615 DOI: 10.1021/acs.nanolett.9b03886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Quantum computing based on superconducting qubits requires the understanding and control of the materials, device architecture, and operation. However, the materials for the central circuit element, the Josephson junction, have mostly been focused on using the AlOx tunnel barrier. Here, we demonstrate Josephson junctions and superconducting qubits employing two-dimensional materials as the tunnel barrier. We batch-fabricate and design the critical Josephson current of these devices via layer-by-layer stacking N layers of MoS2 on the large scale. Based on such junctions, MoS2 transmon qubits are engineered and characterized in a bulk superconducting microwave resonator for the first time. Our work allows Josephson junctions to access the diverse material properties of two-dimensional materials that include a wide range of electrical and magnetic properties, which can be used to study the effects of different material properties in superconducting qubits and to engineer novel quantum circuit elements in the future.
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Affiliation(s)
- Kan-Heng Lee
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
- Pritzker School of Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Srivatsan Chakram
- James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
- Department of Physics , University of Chicago , Chicago , Illinois 60637 , United States
| | - Shi En Kim
- Pritzker School of Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Fauzia Mujid
- Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States
| | - Ariana Ray
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Hui Gao
- Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Chibeom Park
- James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
- Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States
| | - Yu Zhong
- Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States
| | - David A Muller
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - David I Schuster
- Pritzker School of Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
- James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
- Department of Physics , University of Chicago , Chicago , Illinois 60637 , United States
| | - Jiwoong Park
- Pritzker School of Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
- James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
- Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States
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6
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Singh S, Katoch J, Zhu T, Wu RJ, Ahmed AS, Amamou W, Wang D, Mkhoyan KA, Kawakami RK. Strontium Oxide Tunnel Barriers for High Quality Spin Transport and Large Spin Accumulation in Graphene. Nano Lett 2017; 17:7578-7585. [PMID: 29129075 DOI: 10.1021/acs.nanolett.7b03543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The quality of the tunnel barrier at the ferromagnet/graphene interface plays a pivotal role in graphene spin valves by circumventing the impedance mismatch problem, decreasing interfacial spin dephasing mechanisms and decreasing spin absorption back into the ferromagnet. It is thus crucial to integrate superior tunnel barriers to enhance spin transport and spin accumulation in graphene. Here, we employ a novel tunnel barrier, strontium oxide (SrO), onto graphene to realize high quality spin transport as evidenced by room-temperature spin relaxation times exceeding a nanosecond in graphene on silicon dioxide substrates. Furthermore, the smooth and pinhole-free SrO tunnel barrier grown by molecular beam epitaxy (MBE), which can withstand large charge injection current densities, allows us to experimentally realize large spin accumulation in graphene at room temperature. This work puts graphene on the path to achieve efficient manipulation of nanomagnet magnetization using spin currents in graphene for logic and memory applications.
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Affiliation(s)
- Simranjeet Singh
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Jyoti Katoch
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Tiancong Zhu
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Ryan J Wu
- Department of Chemical Engineering and Materials Science, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Adam S Ahmed
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Walid Amamou
- Program of Materials Science and Engineering, University of California , Riverside, California 92521, United States
| | - Dongying Wang
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - K Andre Mkhoyan
- Department of Chemical Engineering and Materials Science, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Roland K Kawakami
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
- Program of Materials Science and Engineering, University of California , Riverside, California 92521, United States
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7
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Avsar A, Tan JY, Luo X, Khoo KH, Yeo Y, Watanabe K, Taniguchi T, Quek SY, Özyilmaz B. van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices. Nano Lett 2017; 17:5361-5367. [PMID: 28792227 DOI: 10.1021/acs.nanolett.7b01817] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Because of the chemical inertness of two dimensional (2D) hexagonal-boron nitride (h-BN), few atomic-layer h-BN is often used to encapsulate air-sensitive 2D crystals such as black phosphorus (BP). However, the effects of h-BN on Schottky barrier height, doping, and contact resistance are not well-known. Here, we investigate these effects by fabricating h-BN encapsulated BP transistors with cobalt (Co) contacts. In sharp contrast to directly Co contacted p-type BP devices, we observe strong n-type conduction upon insertion of the h-BN at the Co/BP interface. First-principles calculations show that this difference arises from the much larger interface dipole at the Co/h-BN interface compared to the Co/BP interface, which reduces the work function of the Co/h-BN contact. The Co/h-BN contacts exhibit low contact resistances (∼4.5 kΩ) and are Schottky barrier-free. This allows us to probe high electron mobilities (4,200 cm2/(V s)) and observe insulator-metal transitions even under two-terminal measurement geometry.
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Affiliation(s)
- Ahmet Avsar
- Centre for Advanced 2D Materials, National University of Singapore , 117542, Singapore
- Department of Physics, National University of Singapore , 117551, Singapore
- Electrical Engineering Institute and Institute of Materials Science and Engineering, École Polytechnique Fed́eŕale de Lausanne (EPFL) , CH-1015, Lausanne, Switzerland
| | - Jun Y Tan
- Centre for Advanced 2D Materials, National University of Singapore , 117542, Singapore
- Department of Physics, National University of Singapore , 117551, Singapore
| | - Xin Luo
- Centre for Advanced 2D Materials, National University of Singapore , 117542, Singapore
- Department of Applied Physics, The Hong Kong Polytechnic University , Hung Hom, Kowloon, Hong Kong, P. R. China
| | - Khoong Hong Khoo
- Institute of High Performance Computing , 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Yuting Yeo
- Centre for Advanced 2D Materials, National University of Singapore , 117542, Singapore
- Department of Physics, National University of Singapore , 117551, Singapore
| | - Kenji Watanabe
- National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Su Ying Quek
- Centre for Advanced 2D Materials, National University of Singapore , 117542, Singapore
- Department of Physics, National University of Singapore , 117551, Singapore
| | - Barbaros Özyilmaz
- Centre for Advanced 2D Materials, National University of Singapore , 117542, Singapore
- Department of Physics, National University of Singapore , 117551, Singapore
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8
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Car D, Conesa-Boj S, Zhang H, Op Het Veld RLM, de Moor MWA, Fadaly EMT, Gül Ö, Kölling S, Plissard SR, Toresen V, Wimmer MT, Watanabe K, Taniguchi T, Kouwenhoven LP, Bakkers EPAM. InSb Nanowires with Built-In Ga xIn 1-xSb Tunnel Barriers for Majorana Devices. Nano Lett 2017; 17:721-727. [PMID: 28173706 DOI: 10.1021/acs.nanolett.6b03835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Majorana zero modes (MZMs), prime candidates for topological quantum bits, are detected as zero bias conductance peaks (ZBPs) in tunneling spectroscopy measurements. Implementation of a narrow and high tunnel barrier in the next generation of Majorana devices can help to achieve the theoretically predicted quantized height of the ZBP. We propose a material-oriented approach to engineer a sharp and narrow tunnel barrier by synthesizing a thin axial segment of GaxIn1-xSb within an InSb nanowire. By varying the precursor molar fraction and the growth time, we accurately control the composition and the length of the barriers. The height and the width of the GaxIn1-xSb tunnel barrier are extracted from the Wentzel-Kramers-Brillouin (WKB) fits to the experimental I-V traces.
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Affiliation(s)
- Diana Car
- Department of Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Sonia Conesa-Boj
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Hao Zhang
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Roy L M Op Het Veld
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Michiel W A de Moor
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Elham M T Fadaly
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Önder Gül
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Sebastian Kölling
- Department of Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | | | - Vigdis Toresen
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Michael T Wimmer
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Leo P Kouwenhoven
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
| | - Erik P A M Bakkers
- Department of Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology , 2628CJ Delft, The Netherlands
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9
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Friedman AL, van 't Erve OMJ, Robinson JT, Whitener KE, Jonker BT. Hydrogenated Graphene as a Homoepitaxial Tunnel Barrier for Spin and Charge Transport in Graphene. ACS Nano 2015; 9:6747-6755. [PMID: 26047069 DOI: 10.1021/acsnano.5b02795] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate that hydrogenated graphene performs as a homoepitaxial tunnel barrier on a graphene charge/spin channel. We examine the tunneling behavior through measuring the IV curves and zero bias resistance. We also fabricate hydrogenated graphene/graphene nonlocal spin valves and measure the spin lifetimes using the Hanle effect, with spintronic nonlocal spin valve operation demonstrated up to room temperature. We show that while hydrogenated graphene indeed allows for spin transport in graphene and has many advantages over oxide tunnel barriers, it does not perform as well as similar fluorinated graphene/graphene devices, possibly due to the presence of magnetic moments in the hydrogenated graphene that act as spin scatterers.
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Affiliation(s)
- Adam L Friedman
- †Materials Science and Technology Division, ‡Electronics Science and Technology Division, and §Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Olaf M J van 't Erve
- †Materials Science and Technology Division, ‡Electronics Science and Technology Division, and §Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Jeremy T Robinson
- †Materials Science and Technology Division, ‡Electronics Science and Technology Division, and §Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Keith E Whitener
- †Materials Science and Technology Division, ‡Electronics Science and Technology Division, and §Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Berend T Jonker
- †Materials Science and Technology Division, ‡Electronics Science and Technology Division, and §Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States
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