1
|
Chakraborti H, Gorini C, Knothe A, Liu MH, Makk P, Parmentier FD, Perconte D, Richter K, Roulleau P, Sacépé B, Schönenberger C, Yang W. Electron wave and quantum optics in graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:393001. [PMID: 38697131 DOI: 10.1088/1361-648x/ad46bc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 05/01/2024] [Indexed: 05/04/2024]
Abstract
In the last decade, graphene has become an exciting platform for electron optical experiments, in some aspects superior to conventional two-dimensional electron gases (2DEGs). A major advantage, besides the ultra-large mobilities, is the fine control over the electrostatics, which gives the possibility of realising gap-less and compact p-n interfaces with high precision. The latter host non-trivial states,e.g., snake states in moderate magnetic fields, and serve as building blocks of complex electron interferometers. Thanks to the Dirac spectrum and its non-trivial Berry phase, the internal (valley and sublattice) degrees of freedom, and the possibility to tailor the band structure using proximity effects, such interferometers open up a completely new playground based on novel device architectures. In this review, we introduce the theoretical background of graphene electron optics, fabrication methods used to realise electron-optical devices, and techniques for corresponding numerical simulations. Based on this, we give a comprehensive review of ballistic transport experiments and simple building blocks of electron optical devices both in single and bilayer graphene, highlighting the novel physics that is brought in compared to conventional 2DEGs. After describing the different magnetic field regimes in graphene p-n junctions and nanostructures, we conclude by discussing the state of the art in graphene-based Mach-Zender and Fabry-Perot interferometers.
Collapse
Affiliation(s)
| | - Cosimo Gorini
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette, France
| | - Angelika Knothe
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Ming-Hao Liu
- Department of Physics and Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan 70101, Taiwan
| | - Péter Makk
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest H-1111, Hungary
- MTA-BME Correlated van der Waals Structures Momentum Research Group, Műegyetem rkp. 3., Budapest H-1111, Hungary
| | | | - David Perconte
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Klaus Richter
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Preden Roulleau
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette, France
| | - Benjamin Sacépé
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | | | - Wenmin Yang
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| |
Collapse
|
2
|
Fu H, Huang K, Watanabe K, Taniguchi T, Zhu J. Charge Oscillations in Bilayer Graphene Quantum Confinement Devices. NANO LETTERS 2023; 23:9726-9732. [PMID: 37862439 DOI: 10.1021/acs.nanolett.3c02253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Quantum confinement structures are building blocks of quantum devices in fundamental physics exploration and technological applications. In this work, we fabricate dual-gated bilayer graphene Fabry-Pérot quantum Hall interferometers employing two different gating strategies and conduct finite element simulations to understand the electrostatics of the confinement structures and to guide device design and fabrication. We observe two types of resistance oscillations arising from the charging of quantum dots formed inside the interferometers. We obtain the size, location, and charging energy of the dots by measuring the dependence of the oscillations on the magnetic field, gate voltages, and dc bias. We analyze and discuss the origin of the quantum dots and their impact on quantum Hall edge state backscattering and interference. Insights gained in these studies shed light on the construction of van der Waals quantum confinement devices.
Collapse
Affiliation(s)
- Hailong Fu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Ke Huang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Jun Zhu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| |
Collapse
|
3
|
Ingla-Aynés J, Manesco ALR, Ghiasi TS, Volosheniuk S, Watanabe K, Taniguchi T, van der Zant HSJ. Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene. NANO LETTERS 2023; 23:5453-5459. [PMID: 37289250 PMCID: PMC10311585 DOI: 10.1021/acs.nanolett.3c00499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/02/2023] [Indexed: 06/09/2023]
Abstract
We report multiterminal measurements in a ballistic bilayer graphene (BLG) channel, where multiple spin- and valley-degenerate quantum point contacts (QPCs) are defined by electrostatic gating. By patterning QPCs of different shapes along different crystallographic directions, we study the effect of size quantization and trigonal warping on transverse electron focusing (TEF). Our TEF spectra show eight clear peaks with comparable amplitudes and weak signatures of quantum interference at the lowest temperature, indicating that reflections at the gate-defined edges are specular, and transport is phase coherent. The temperature dependence of the focusing signal shows that, despite the small gate-induced bandgaps in our sample (≲45 meV), several peaks are visible up to 100 K. The achievement of specular reflection, which is expected to preserve the pseudospin information of the electron jets, is promising for the realization of ballistic interconnects for new valleytronic devices.
Collapse
Affiliation(s)
- Josep Ingla-Aynés
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Antonio L. R. Manesco
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Talieh S. Ghiasi
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Serhii Volosheniuk
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Herre S. J. van der Zant
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| |
Collapse
|
4
|
Ekanayaka T, Jiang T, Delahaye E, Perez O, Sutter JP, Le D, N'Diaye AT, Streubel R, Rahman TS, Dowben PA. Evidence of symmetry breaking in a Gd 2 di-nuclear molecular polymer. Phys Chem Chem Phys 2023; 25:6416-6423. [PMID: 36779815 DOI: 10.1039/d2cp03050k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A chiral 3D coordination compound, [Gd2(L)2(ox)2(H2O)2], arranged around a dinuclear Gd unit has been characterized by X-ray photoemission and X-ray absorption measurements in the context of density functional theory studies. Core level photoemission of the Gd 5p multiplet splittings indicates that spin orbit coupling dominates over j-J coupling evident in the 5p core level spectra of Gd metal. Indications of spin-orbit coupling are consistent with the absence of inversion symmetry due to the ligand field. Density functional theory predicts antiferromagnet alignment of the Gd2 dimers and a band gap of the compound consistent with optical absorption.
Collapse
Affiliation(s)
- Thilini Ekanayaka
- Department of Physics and Astronomy, Theodore Jorgensen Hall, 855 North 16th Street, University of Nebraska-Lincoln, Lincoln, NE, 68588-0299, USA.
| | - Tao Jiang
- Department of Physics, University of Central Florida, 4000 Central Florida Blvd, Building 121 PS 430, Orlando, FL, 32816, USA.
| | - Emilie Delahaye
- Laboratoire de Chimie de Coordination du CNRS (LCC), Université de Toulouse, CNRS, Toulouse, France.
| | - Olivier Perez
- Normandie Univ, ENSICAEN, Unicaen, CNRS, CRISMAT, 14000, Caen, France
| | - Jean-Pascal Sutter
- Laboratoire de Chimie de Coordination du CNRS (LCC), Université de Toulouse, CNRS, Toulouse, France.
| | - Duy Le
- Department of Physics, University of Central Florida, 4000 Central Florida Blvd, Building 121 PS 430, Orlando, FL, 32816, USA.
| | - Alpha T N'Diaye
- Lawrence Berkeley National Laboratory, Advanced Light Source, Berkeley, CA, 94720, USA
| | - Robert Streubel
- Department of Physics and Astronomy, Theodore Jorgensen Hall, 855 North 16th Street, University of Nebraska-Lincoln, Lincoln, NE, 68588-0299, USA.
| | - Talat S Rahman
- Department of Physics, University of Central Florida, 4000 Central Florida Blvd, Building 121 PS 430, Orlando, FL, 32816, USA.
| | - Peter A Dowben
- Department of Physics and Astronomy, Theodore Jorgensen Hall, 855 North 16th Street, University of Nebraska-Lincoln, Lincoln, NE, 68588-0299, USA.
| |
Collapse
|
5
|
Jo M, Lee JYM, Assouline A, Brasseur P, Watanabe K, Taniguchi T, Roche P, Glattli DC, Kumada N, Parmentier FD, Sim HS, Roulleau P. Scaling behavior of electron decoherence in a graphene Mach-Zehnder interferometer. Nat Commun 2022; 13:5473. [PMID: 36115841 PMCID: PMC9482640 DOI: 10.1038/s41467-022-33078-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 08/30/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractOver the past 20 years, many efforts have been made to understand and control decoherence in 2D electron systems. In particular, several types of electronic interferometers have been considered in GaAs heterostructures, in order to protect the interfering electrons from decoherence. Nevertheless, it is now understood that several intrinsic decoherence sources fundamentally limit more advanced quantum manipulations. Here, we show that graphene offers a unique possibility to reach a regime where the decoherence is frozen and to study unexplored regimes of electron interferometry. We probe the decoherence of electron channels in a graphene quantum Hall PN junction, forming a Mach-Zehnder interferometer1,2, and unveil a scaling behavior of decay of the interference visibility with the temperature scaled by the interferometer length. It exhibits a remarkable crossover from an exponential decay at higher temperature to an algebraic decay at lower temperature where almost no decoherence occurs, a regime previously unobserved in GaAs interferometers.
Collapse
|
6
|
Le Breton G, Delagrange R, Hong Y, Garg M, Watanabe K, Taniguchi T, Ribeiro-Palau R, Roulleau P, Roche P, Parmentier FD. Heat Equilibration of Integer and Fractional Quantum Hall Edge Modes in Graphene. PHYSICAL REVIEW LETTERS 2022; 129:116803. [PMID: 36154417 DOI: 10.1103/physrevlett.129.116803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/01/2022] [Indexed: 06/16/2023]
Abstract
Hole-conjugate states of the fractional quantum Hall effect host counterpropagating edge channels which are thought to exchange charge and energy. These exchanges have been the subject of extensive theoretical and experimental works; in particular, it is yet unclear if the presence of integer quantum Hall edge channels stemming from fully filled Landau levels affects heat equilibration along the edge. In this Letter, we present heat transport measurements in quantum Hall states of graphene demonstrating that the integer channels can strongly equilibrate with the fractional ones, leading to markedly different regimes of quantized heat transport that depend on edge electrostatics. Our results allow for a better comprehension of the complex edge physics in the fractional quantum Hall regime.
Collapse
Affiliation(s)
- G Le Breton
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette cedex, France
| | - R Delagrange
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette cedex, France
| | - Y Hong
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 91120 Palaiseau, France
| | - M Garg
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette cedex, France
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, 305-0044 Tsukuba, Japan
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, 305-0044 Tsukuba, Japan
| | - R Ribeiro-Palau
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 91120 Palaiseau, France
| | - P Roulleau
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette cedex, France
| | - P Roche
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette cedex, France
| | - F D Parmentier
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette cedex, France
| |
Collapse
|
7
|
Dhingra A, Hu X, Borunda MF, Johnson JF, Binek C, Bird J, N'Diaye AT, Sutter JP, Delahaye E, Switzer ED, Barco ED, Rahman TS, Dowben PA. Molecular transistors as substitutes for quantum information applications. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:441501. [PMID: 35998608 DOI: 10.1088/1361-648x/ac8c11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
Applications of quantum information science (QIS) generally rely on the generation and manipulation of qubits. Still, there are ways to envision a device with a continuous readout, but without the entangled states. This concise perspective includes a discussion on an alternative to the qubit, namely the solid-state version of the Mach-Zehnder interferometer, in which the local moments and spin polarization replace light polarization. In this context, we provide some insights into the mathematics that dictates the fundamental working principles of quantum information processes that involve molecular systems with large magnetic anisotropy. Transistors based on such systems lead to the possibility of fabricating logic gates that do not require entangled states. Furthermore, some novel approaches, worthy of some consideration, exist to address the issues pertaining to the scalability of quantum devices, but face the challenge of finding the suitable materials for desired functionality that resemble what is sought from QIS devices.
Collapse
Affiliation(s)
- Archit Dhingra
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588-0299, United States of America
| | - Xuedong Hu
- Department of Physics, University at Buffalo, Buffalo, NY, 14260-1500, United States of America
| | - Mario F Borunda
- Department of Physics, Oklahoma State University, Stillwater, OK 74078, United States of America
| | - Joseph F Johnson
- Department of Mathematics & Statistics, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States of America
| | - Christian Binek
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588-0299, United States of America
- Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588-0299, United States of America
| | - Jonathan Bird
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260-1900, United States of America
| | - Alpha T N'Diaye
- Advanced Light Source (ALS, BL631), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
| | - Jean-Pascal Sutter
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, F-31000 Toulouse, France
| | - Emilie Delahaye
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, F-31000 Toulouse, France
| | - Eric D Switzer
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
| | - Enrique Del Barco
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
| | - Peter A Dowben
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588-0299, United States of America
| |
Collapse
|
8
|
Choi MS, Ali N, Ngo TD, Choi H, Oh B, Yang H, Yoo WJ. Recent Progress in 1D Contacts for 2D-Material-Based Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202408. [PMID: 35594170 DOI: 10.1002/adma.202202408] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Recent studies have intensively examined 2D materials (2DMs) as promising materials for use in future quantum devices due to their atomic thinness. However, a major limitation occurs when 2DMs are in contact with metals: a van der Waals (vdW) gap is generated at the 2DM-metal interfaces, which induces metal-induced gap states that are responsible for an uncontrollable Schottky barrier (SB), Fermi-level pinning (FLP), and high contact resistance (RC ), thereby substantially lowering the electronic mobility of 2DM-based devices. Here, vdW-gap-free 1D edge contact is reviewed for use in 2D devices with substantially suppressed carrier scattering of 2DMs with hexagonal boron nitride (hBN) encapsulation. The 1D contact further enables uniform carrier transport across multilayered 2DM channels, high-density transistor integration independent of scaling, and the fabrication of double-gate transistors suitable for demonstrating unique quantum phenomena of 2DMs. The existing 1D contact methods are reviewed first. As a promising technology toward the large-scale production of 2D devices, seamless lateral contacts are reviewed in detail. The electronic, optoelectronic, and quantum devices developed via 1D contacts are subsequently discussed. Finally, the challenges regarding the reliability of 1D contacts are addressed, followed by an outlook of 1D contact methods.
Collapse
Affiliation(s)
- Min Sup Choi
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, 16419, Korea
| | - Nasir Ali
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, 16419, Korea
| | - Tien Dat Ngo
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, 16419, Korea
| | - Hyungyu Choi
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, 16419, Korea
| | - Byungdu Oh
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, 16419, Korea
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Won Jong Yoo
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, 16419, Korea
| |
Collapse
|
9
|
Nicolí G, Adam C, Röösli MP, Märki P, Scharnetzky J, Reichl C, Wegscheider W, Ihn TM, Ensslin K. Spin-Selective Equilibration among Integer Quantum Hall Edge Channels. PHYSICAL REVIEW LETTERS 2022; 128:056802. [PMID: 35179909 DOI: 10.1103/physrevlett.128.056802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 01/03/2022] [Accepted: 01/10/2022] [Indexed: 06/14/2023]
Abstract
The equilibration between quantum Hall edge modes is known to depend on the disorder potential and the steepness of the edge. Modern samples with higher mobilities and setups with lower electron temperatures call for a further exploration of the topic. We develop a framework to systematically measure and analyze the equilibration of many (up to 8) integer edge modes. Our results show that spin-selective coupling dominates even for non-neighboring channels with parallel spin. Changes in magnetic field and bulk density let us control the equilibration until it is almost completely suppressed and dominated only by individual microscopic scatterers. This method could serve as a guideline to investigate and design improved devices, and to study fractional and other exotic states.
Collapse
Affiliation(s)
- Giorgio Nicolí
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | - Christoph Adam
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | - Marc P Röösli
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | - Peter Märki
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | - Jan Scharnetzky
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | - Christian Reichl
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Thomas M Ihn
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| | - Klaus Ensslin
- Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
| |
Collapse
|
10
|
Bakare OO, Keyster M, Pretorius A. Building HMM and molecular docking analysis for the sensitive detection of anti-viral pneumonia antimicrobial peptides (AMPs). Sci Rep 2021; 11:20621. [PMID: 34663864 PMCID: PMC8523717 DOI: 10.1038/s41598-021-00223-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/06/2021] [Indexed: 01/13/2023] Open
Abstract
Pneumonia is the main reason for mortality among children under five years, causing 1.6 million deaths every year; late research has exhibited that mortality is increasing in the elderly. A few biomarkers used for its diagnosis need specificity and precision, as they are related to different infections, for example, pulmonary tuberculosis and Human Immunodeficiency Virus. There is a quest for new biomarkers worldwide to diagnose the disease to defeat these previously mentioned constraints. Antimicrobial peptides (AMPs) are promising indicative specialists against infection. This research work used AMPs as biomarkers to detect viral pneumonia pathogens, for example, Respiratory syncytial virus, Influenza A and B viruses utilizing in silico technologies, such as Hidden Markov Model (HMMER). HMMER was used to distinguish putative anti-viral pneumonia AMPs against the recognized receptor proteins of Respiratory syncytial virus, Influenza A, and B viruses. The physicochemical parameters of these putative AMPs were analyzed, and their 3-D structures were determined utilizing I-TASSER. Molecular docking interaction of these AMPs against the recognized viral pneumonia proteins was carried out using the PATCHDOCK and HDock servers. The results demonstrated 27 anti-viral AMPs ranked based on their E values with significant physicochemical parameters in similarity with known experimentally approved AMPs. The AMPs additionally had a high anticipated binding potential to the pneumonia receptors of these microorganisms sensitively. The tendency of the putative anti-viral AMPs to bind pneumonia proteins showed that they would be promising applicant biomarkers to identify these viral microorganisms in the point-of-care (POC) pneumonia diagnostics. The high precision observed for the AMPs legitimizes HMM's utilization in the disease diagnostics' discovery process.
Collapse
Affiliation(s)
- Olalekan Olanrewaju Bakare
- Bioinformatics Research Group, University of the Western Cape, Cape Town, 7535, South Africa.
- Environmental Biotechnology Laboratory, Biotechnology Department, University of the Western Cape, Cape Town, 7535, South Africa.
| | - Marshall Keyster
- Environmental Biotechnology Laboratory, Biotechnology Department, University of the Western Cape, Cape Town, 7535, South Africa
| | - Ashley Pretorius
- Bioinformatics Research Group, University of the Western Cape, Cape Town, 7535, South Africa
| |
Collapse
|
11
|
Moreau N, Brun B, Somanchi S, Watanabe K, Taniguchi T, Stampfer C, Hackens B. Upstream modes and antidots poison graphene quantum Hall effect. Nat Commun 2021; 12:4265. [PMID: 34253725 PMCID: PMC8275581 DOI: 10.1038/s41467-021-24481-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/17/2021] [Indexed: 11/09/2022] Open
Abstract
The quantum Hall effect is the seminal example of topological protection, as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. Graphene has made its marks as an exceptional platform to reveal new facets of this remarkable property. However, in conventional Hall bar geometries, topological protection of graphene edge channels is found regrettably less robust than in high mobility semi-conductors. Here, we explore graphene quantum Hall regime at the local scale, using a scanning gate microscope. We reveal the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels, hence triggering topological breakdown. Combined with simulations, our experimental results provide further insights into graphene quantum Hall channels vulnerability. In turn, this may ease future developments towards precise manipulation of topologically protected edge channels hosted in various types of two-dimensional crystals.
Collapse
Affiliation(s)
- N Moreau
- IMCN/NAPS, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | - B Brun
- IMCN/NAPS, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | - S Somanchi
- JARA-FIT and 2nd Institute of Physics-RWTH Aachen, Aachen, Germany
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - C Stampfer
- JARA-FIT and 2nd Institute of Physics-RWTH Aachen, Aachen, Germany
| | - B Hackens
- IMCN/NAPS, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium.
| |
Collapse
|
12
|
Lotfizadeh N, Senger MJ, McCulley DR, Minot ED, Deshpande VV. Quantum Interferences in Ultraclean Carbon Nanotubes. PHYSICAL REVIEW LETTERS 2021; 126:216802. [PMID: 34114831 DOI: 10.1103/physrevlett.126.216802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
Electronic analogs of optical interferences are powerful tools to investigate quantum phenomena in condensed matter. In carbon nanotubes (CNTs), it is well established that an electronic Fabry-Perot interferometer can be realized. Other types of quantum interferences should also arise in CNTs, but have proven challenging to realize. In particular, CNTs have been identified as a system to realize the electronic analog of a Sagnac interferometer-the most sensitive optical interferometer. To realize this Sagnac effect, interference between nonidentical transmission channels in a single CNT must be observed. Here, we use suspended, ultraclean CNTs of known chiral index to study both Fabry-Perot and Sagnac electron interferences. We verify theoretical predictions for the behavior of Sagnac oscillations and the persistence of the Sagnac oscillations at high temperatures. As suggested by existing theoretical studies, our results show that these quantum interferences may be used for electronic structure characterization of carbon nanotubes and the study of many-body effects in these model one-dimensional systems.
Collapse
Affiliation(s)
- Neda Lotfizadeh
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - Mitchell J Senger
- Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Daniel R McCulley
- Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Ethan D Minot
- Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Vikram V Deshpande
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| |
Collapse
|
13
|
Ronen Y, Werkmeister T, Haie Najafabadi D, Pierce AT, Anderson LE, Shin YJ, Lee SY, Lee YH, Johnson B, Watanabe K, Taniguchi T, Yacoby A, Kim P. Aharonov-Bohm effect in graphene-based Fabry-Pérot quantum Hall interferometers. NATURE NANOTECHNOLOGY 2021; 16:563-569. [PMID: 33633404 DOI: 10.1038/s41565-021-00861-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Interferometers probe the wave-nature and exchange statistics of indistinguishable particles-for example, electrons in the chiral one-dimensional edge channels of the quantum Hall effect (QHE). Quantum point contacts can split and recombine these channels, enabling interference of charged particles. Such quantum Hall interferometers (QHIs) can unveil the exchange statistics of anyonic quasi-particles in the fractional quantum Hall effect (FQHE). Here, we present a fabrication technique for QHIs in van der Waals (vdW) materials and realize a tunable, graphene-based Fabry-Pérot (FP) QHI. The graphite-encapsulated architecture allows observation of FQHE at a magnetic field of 3T and precise partitioning of integer and fractional edge modes. We measure pure Aharonov-Bohm interference in the integer QHE, a major technical challenge in small FP interferometers, and find that edge modes exhibit high-visibility interference due to large velocities. Our results establish vdW heterostructures as a versatile alternative to GaAs-based interferometers for future experiments targeting anyonic quasi-particles.
Collapse
Affiliation(s)
- Yuval Ronen
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Thomas Werkmeister
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | | | - Andrew T Pierce
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Young Jae Shin
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA
| | - Si Young Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon, Republic of Korea
| | - Bobae Johnson
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Amir Yacoby
- Department of Physics, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
| |
Collapse
|
14
|
Déprez C, Veyrat L, Vignaud H, Nayak G, Watanabe K, Taniguchi T, Gay F, Sellier H, Sacépé B. A tunable Fabry-Pérot quantum Hall interferometer in graphene. NATURE NANOTECHNOLOGY 2021; 16:555-562. [PMID: 33633403 PMCID: PMC7610789 DOI: 10.1038/s41565-021-00847-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/06/2021] [Indexed: 05/27/2023]
Abstract
Electron interferometry with quantum Hall (QH) edge channels in semiconductor heterostructures can probe and harness the exchange statistics of anyonic excitations. However, the charging effects present in semiconductors often obscure the Aharonov-Bohm interference in QH interferometers and make advanced charge-screening strategies necessary. Here we show that high-mobility monolayer graphene constitutes an alternative material system, not affected by charging effects, for performing Fabry-Pérot QH interferometry in the integer QH regime. In devices equipped with gate-tunable quantum point contacts acting on the edge channels of the zeroth Landau level, we observe-in agreement with theory-high-visibility Aharonov-Bohm interference widely tunable through electrostatic gating or magnetic fields. A coherence length of 10 μm at a temperature of 0.02 K allows us to further achieve coherently coupled double Fabry-Pérot interferometry. In future, QH interferometry with graphene devices may enable investigations of anyonic excitations in fractional QH states.
Collapse
Affiliation(s)
- Corentin Déprez
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Louis Veyrat
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Hadrien Vignaud
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Goutham Nayak
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Frédéric Gay
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Hermann Sellier
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Benjamin Sacépé
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France.
| |
Collapse
|
15
|
Jo M, Brasseur P, Assouline A, Fleury G, Sim HS, Watanabe K, Taniguchi T, Dumnernpanich W, Roche P, Glattli DC, Kumada N, Parmentier FD, Roulleau P. Quantum Hall Valley Splitters and a Tunable Mach-Zehnder Interferometer in Graphene. PHYSICAL REVIEW LETTERS 2021; 126:146803. [PMID: 33891444 DOI: 10.1103/physrevlett.126.146803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
Graphene is a very promising test bed for the field of electron quantum optics. However, a fully tunable and coherent electronic beam splitter is still missing. We report the demonstration of electronic beam splitters in graphene that couple quantum Hall edge channels having opposite valley polarizations. The electronic transmission of our beam splitters can be tuned from zero to near unity. By independently setting the beam splitters at the two corners of a graphene p-n junction to intermediate transmissions, we realize a fully tunable electronic Mach-Zehnder interferometer. This tunability allows us to unambiguously identify the quantum interferences due to the Mach-Zehnder interferometer, and to study their dependence with the beam-splitter transmission and the interferometer bias voltage. The comparison with conventional semiconductor interferometers points toward universal processes driving the quantum decoherence in those two different 2D systems, with graphene being much more robust to their effect.
Collapse
Affiliation(s)
- M Jo
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - P Brasseur
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - A Assouline
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - G Fleury
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - H-S Sim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - W Dumnernpanich
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - P Roche
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - D C Glattli
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - N Kumada
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198, Japan
| | - F D Parmentier
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| | - P Roulleau
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex France
| |
Collapse
|
16
|
Mills SM, Averin DV, Du X. Localizing Fractional Quasiparticles on Graphene Quantum Hall Antidots. PHYSICAL REVIEW LETTERS 2020; 125:227701. [PMID: 33315430 DOI: 10.1103/physrevlett.125.227701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 10/26/2020] [Indexed: 06/12/2023]
Abstract
We report localization of fractional quantum Hall (QH) quasiparticles on graphene antidots. By studying coherent tunneling through the localized QH edge modes on the antidot, we measured the QH quasiparticle charges to be approximately ±e/3 at fractional fillings of ν=±1/3. The Dirac spectrum in graphene allows large energy scales and robust quasiparticle localization against thermal excitation. The capability of localizing fractional quasiparticles on QH antidots brings promising opportunities for realizing anyon braiding and novel quantum electronics.
Collapse
Affiliation(s)
- S M Mills
- Department of Physics, Stony Brook University, Stony Brook, New York 11794, USA
| | - D V Averin
- Department of Physics, Stony Brook University, Stony Brook, New York 11794, USA
| | - X Du
- Department of Physics, Stony Brook University, Stony Brook, New York 11794, USA
| |
Collapse
|
17
|
Bakare OO, Fadaka AO, Klein A, Pretorius A. Dietary effects of antimicrobial peptides in therapeutics. ALL LIFE 2020. [DOI: 10.1080/26895293.2020.1726826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Affiliation(s)
- Olalekan Olanrewaju Bakare
- Department of Biotechnology, Faculty of Natural Sciences, University of the Western Cape, Cape Town, South Africa
| | - Adewale Oluwaseun Fadaka
- Department of Biotechnology, Faculty of Natural Sciences, University of the Western Cape, Cape Town, South Africa
| | - Ashwil Klein
- Department of Biotechnology, Faculty of Natural Sciences, University of the Western Cape, Cape Town, South Africa
| | - Ashley Pretorius
- Department of Biotechnology, Faculty of Natural Sciences, University of the Western Cape, Cape Town, South Africa
| |
Collapse
|
18
|
Wang K, Harzheim A, Taniguchi T, Watanabei K, Lee JU, Kim P. Tunneling Spectroscopy of Quantum Hall States in Bilayer Graphene p-n Junctions. PHYSICAL REVIEW LETTERS 2019; 122:146801. [PMID: 31050489 DOI: 10.1103/physrevlett.122.146801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 01/08/2019] [Indexed: 06/09/2023]
Abstract
We report tunneling transport in spatially controlled networks of quantum Hall (QH) edge states in bilayer graphene. By manipulating the separation, location, and spatial span of QH edge states via gate-defined electrostatics, we observe resonant tunneling between copropagating QH states across incompressible strips. Employing spectroscopic tunneling measurements and an analytical model, we characterize the energy gap, width, density of states, and compressibility of the QH edge states with high precision and sensitivity within the same device. The capability to engineer the QH edge network also provides an opportunity to build future quantum electronic devices with electrostatic manipulation of QH edge states, supported by rich underlying physics.
Collapse
Affiliation(s)
- Ke Wang
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55116, USA
| | - Achim Harzheim
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Takashi Taniguchi
- National Institute for Materials Science, Namiki, Ibaraki 305-0044, Japan
| | - Kenji Watanabei
- National Institute for Materials Science, Namiki, Ibaraki 305-0044, Japan
| | - Ji Ung Lee
- College of Nanoscale Engineering and Technology Innovation, SUNY Polytechnic Institute, Albany, New York 12203, USA
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| |
Collapse
|
19
|
Ribeiro-Palau R, Chen S, Zeng Y, Watanabe K, Taniguchi T, Hone J, Dean CR. High-Quality Electrostatically Defined Hall Bars in Monolayer Graphene. NANO LETTERS 2019; 19:2583-2587. [PMID: 30839210 DOI: 10.1021/acs.nanolett.9b00351] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Realizing graphene's promise as an atomically thin and tunable platform for fundamental studies and future applications in quantum transport requires the ability to electrostatically define the geometry of the structure and control the carrier concentration, without compromising the quality of the system. Here, we demonstrate the working principle of a new generation of high-quality gate-defined graphene samples, where the challenge of doing so in a gapless semiconductor is overcome by using the ν = 0 insulating state, which emerges at modest applied magnetic fields. In order to verify that the quality of our devices is not compromised, we compare the electronic transport response of different sample geometries, paying close attention to fragile quantum states, such as the fractional quantum Hall states that are highly susceptible to disorder. The ability to define local depletion regions without compromising device quality establishes a new approach toward structuring graphene-based quantum transport devices.
Collapse
Affiliation(s)
- Rebeca Ribeiro-Palau
- Department of Physics , Columbia University , New York , New York 10027 , United States
- Department of Mechanical Engineering , Columbia University , New York , New York 10027 , United States
| | - Shaowen Chen
- Department of Physics , Columbia University , New York , New York 10027 , United States
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - Yihang Zeng
- Department of Physics , Columbia University , New York , New York 10027 , United States
| | - 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
| | - James Hone
- Department of Mechanical Engineering , Columbia University , New York , New York 10027 , United States
| | - Cory R Dean
- Department of Physics , Columbia University , New York , New York 10027 , United States
| |
Collapse
|
20
|
Ahmad NF, Komatsu K, Iwasaki T, Watanabe K, Taniguchi T, Mizuta H, Wakayama Y, Hashim AM, Morita Y, Moriyama S, Nakaharai S. Fabry-Pérot resonances and a crossover to the quantum Hall regime in ballistic graphene quantum point contacts. Sci Rep 2019; 9:3031. [PMID: 30816251 PMCID: PMC6395604 DOI: 10.1038/s41598-019-39909-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/04/2019] [Indexed: 11/09/2022] Open
Abstract
We report on the observation of quantum transport and interference in a graphene device that is attached with a pair of split gates to form an electrostatically-defined quantum point contact (QPC). In the low magnetic field regime, the resistance exhibited Fabry-Pérot (FP) resonances due to np'n(pn'p) cavities formed by the top gate. In the quantum Hall (QH) regime with a high magnetic field, the edge states governed the phenomena, presenting a unique condition where the edge channels of electrons and holes along a p-n junction acted as a solid-state analogue of a monochromatic light beam. We observed a crossover from the FP to QH regimes in ballistic graphene QPC under a magnetic field with varying temperatures. In particular, the collapse of the QH effect was elucidated as the magnetic field was decreased. Our high-mobility graphene device enabled observation of such quantum coherence effects up to several tens of kelvins. The presented device could serve as one of the key elements in future electronic quantum optic devices.
Collapse
Grants
- 15K21722 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JPMJCR15F3 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 15K21722 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JPMJCR15F3 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 26630139 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
Collapse
Affiliation(s)
- Nurul Fariha Ahmad
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan
- Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100, Kuala Lumpur, Malaysia
| | - Katsuyoshi Komatsu
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan
| | - Takuya Iwasaki
- International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, NIMS, Tsukuba, Ibaraki, 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Functional Materials, NIMS, Tsukuba, Ibaraki, 305-0044, Japan
| | - Hiroshi Mizuta
- School of Material Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1211, Japan
- Hitachi Cambridge Laboratory, Hitachi Europe Ltd., J. J. Thomson Avenue, Cambridge, United Kingdom
| | - Yutaka Wakayama
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan
| | - Abdul Manaf Hashim
- Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100, Kuala Lumpur, Malaysia
| | - Yoshifumi Morita
- Faculty of Engineering, Gunma University, Kiryu, Gunma, 376-8515, Japan
| | - Satoshi Moriyama
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan
| | - Shu Nakaharai
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan.
| |
Collapse
|
21
|
Wei DS, van der Sar T, Lee SH, Watanabe K, Taniguchi T, Halperin BI, Yacoby A. Electrical generation and detection of spin waves in a quantum Hall ferromagnet. Science 2018; 362:229-233. [PMID: 30309954 DOI: 10.1126/science.aar4061] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 08/19/2018] [Indexed: 11/02/2022]
Abstract
Spin waves are collective excitations of magnetic systems. An attractive setting for studying long-lived spin-wave physics is the quantum Hall (QH) ferromagnet, which forms spontaneously in clean two-dimensional electron systems at low temperature and in a perpendicular magnetic field. We used out-of-equilibrium occupation of QH edge channels in graphene to excite and detect spin waves in magnetically ordered QH states. Our experiments provide direct evidence for long-distance spin-wave propagation through different ferromagnetic phases in the N = 0 Landau level, as well as across the insulating canted antiferromagnetic phase. Our results will enable experimental investigation of the fundamental magnetic properties of these exotic two-dimensional electron systems.
Collapse
Affiliation(s)
- Di S Wei
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | | | - Seung Hwan Lee
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | | | - Amir Yacoby
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. .,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| |
Collapse
|
22
|
Zibrov AA, Kometter C, Zhou H, Spanton EM, Taniguchi T, Watanabe K, Zaletel MP, Young AF. Tunable interacting composite fermion phases in a half-filled bilayer-graphene Landau level. Nature 2017; 549:360-364. [DOI: 10.1038/nature23893] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 07/26/2017] [Indexed: 11/09/2022]
|