1
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Krieger JA, Stolz S, Robredo I, Manna K, McFarlane EC, Date M, Pal B, Yang J, B Guedes E, Dil JH, Polley CM, Leandersson M, Shekhar C, Borrmann H, Yang Q, Lin M, Strocov VN, Caputo M, Watson MD, Kim TK, Cacho C, Mazzola F, Fujii J, Vobornik I, Parkin SSP, Bradlyn B, Felser C, Vergniory MG, Schröter NBM. Weyl spin-momentum locking in a chiral topological semimetal. Nat Commun 2024; 15:3720. [PMID: 38697958 PMCID: PMC11066003 DOI: 10.1038/s41467-024-47976-0] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 04/17/2024] [Indexed: 05/05/2024] Open
Abstract
Spin-orbit coupling in noncentrosymmetric crystals leads to spin-momentum locking - a directional relationship between an electron's spin angular momentum and its linear momentum. Isotropic orthogonal Rashba spin-momentum locking has been studied for decades, while its counterpart, isotropic parallel Weyl spin-momentum locking has remained elusive in experiments. Theory predicts that Weyl spin-momentum locking can only be realized in structurally chiral cubic crystals in the vicinity of Kramers-Weyl or multifold fermions. Here, we use spin- and angle-resolved photoemission spectroscopy to evidence Weyl spin-momentum locking of multifold fermions in the chiral topological semimetal PtGa. We find that the electron spin of the Fermi arc surface states is orthogonal to their Fermi surface contour for momenta close to the projection of the bulk multifold fermion at the Γ point, which is consistent with Weyl spin-momentum locking of the latter. The direct measurement of the bulk spin texture of the multifold fermion at the R point also displays Weyl spin-momentum locking. The discovery of Weyl spin-momentum locking may lead to energy-efficient memory devices and Josephson diodes based on chiral topological semimetals.
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Affiliation(s)
- Jonas A Krieger
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Samuel Stolz
- Department of Physics, University of California, Berkeley, CA, USA
- nanotech@surfaces Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600, Dübendorf, Switzerland
| | - Iñigo Robredo
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
- Donostia International Physics Center, 20018, Donostia - San Sebastian, Spain
| | - Kaustuv Manna
- Indian Institute of Technology-Delhi, Hauz Khas, New Delhi, 110 016, India
| | - Emily C McFarlane
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - Mihir Date
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - Banabir Pal
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - Jiabao Yang
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - Eduardo B Guedes
- Photon Science Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
- Institut de Physique, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - J Hugo Dil
- Photon Science Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
- Institut de Physique, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Craig M Polley
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484, Lund, Sweden
| | - Mats Leandersson
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484, Lund, Sweden
| | - Chandra Shekhar
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Horst Borrmann
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Qun Yang
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Mao Lin
- Department of Physics, University of Illinois, Urbana-Champaign, USA
| | - Vladimir N Strocov
- Photon Science Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
| | - Marco Caputo
- Photon Science Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
| | - Matthew D Watson
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Timur K Kim
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Cephise Cacho
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Federico Mazzola
- Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Trieste, I-34149, Italy
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, 30172, Venice, Italy
| | - Jun Fujii
- CNR-IOM, Area Science Park, Strada Statale 14 km 163.5, I-34149, Trieste, Italy
| | - Ivana Vobornik
- CNR-IOM, Area Science Park, Strada Statale 14 km 163.5, I-34149, Trieste, Italy
| | - Stuart S P Parkin
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - Barry Bradlyn
- Department of Physics, University of Illinois, Urbana-Champaign, USA
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Maia G Vergniory
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
- Donostia International Physics Center, 20018, Donostia - San Sebastian, Spain
| | - Niels B M Schröter
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany.
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2
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Belopolski I, Chang G, Cochran TA, Cheng ZJ, Yang XP, Hugelmeyer C, Manna K, Yin JX, Cheng G, Multer D, Litskevich M, Shumiya N, Zhang SS, Shekhar C, Schröter NBM, Chikina A, Polley C, Thiagarajan B, Leandersson M, Adell J, Huang SM, Yao N, Strocov VN, Felser C, Hasan MZ. Observation of a linked-loop quantum state in a topological magnet. Nature 2022; 604:647-652. [PMID: 35478239 DOI: 10.1038/s41586-022-04512-8] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 02/03/2022] [Indexed: 11/09/2022]
Abstract
Quantum phases can be classified by topological invariants, which take on discrete values capturing global information about the quantum state1-13. Over the past decades, these invariants have come to play a central role in describing matter, providing the foundation for understanding superfluids5, magnets6,7, the quantum Hall effect3,8, topological insulators9,10, Weyl semimetals11-13 and other phenomena. Here we report an unusual linking-number (knot theory) invariant associated with loops of electronic band crossings in a mirror-symmetric ferromagnet14-20. Using state-of-the-art spectroscopic methods, we directly observe three intertwined degeneracy loops in the material's three-torus, T3, bulk Brillouin zone. We find that each loop links each other loop twice. Through systematic spectroscopic investigation of this linked-loop quantum state, we explicitly draw its link diagram and conclude, in analogy with knot theory, that it exhibits the linking number (2, 2, 2), providing a direct determination of the invariant structure from the experimental data. We further predict and observe, on the surface of our samples, Seifert boundary states protected by the bulk linked loops, suggestive of a remarkable Seifert bulk-boundary correspondence. Our observation of a quantum loop link motivates the application of knot theory to the exploration of magnetic and superconducting quantum matter.
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Affiliation(s)
- Ilya Belopolski
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA. .,RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, Japan.
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Tyler A Cochran
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Xian P Yang
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Cole Hugelmeyer
- Department of Mathematics, Princeton University, Princeton, NJ, USA
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.,Department of Physics, Indian Institute of Technology Delhi, New Delhi, India
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Maksim Litskevich
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Nana Shumiya
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Songtian S Zhang
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA
| | - Chandra Shekhar
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | | | - Alla Chikina
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Craig Polley
- MAX IV Laboratory, Lund University, Lund, Sweden
| | | | | | - Johan Adell
- MAX IV Laboratory, Lund University, Lund, Sweden
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung City, Taiwan
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA
| | | | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, NJ, USA. .,Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Quantum Science Center, Oak Ridge, TN, USA.
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3
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Pal B, Chakraborty A, Sivakumar PK, Davydova M, Gopi AK, Pandeya AK, Krieger JA, Zhang Y, Date M, Ju S, Yuan N, Schröter NBM, Fu L, Parkin SSP. Josephson diode effect from Cooper pair momentum in a topological semimetal. Nat Phys 2022; 18:1228-1233. [PMID: 36217362 PMCID: PMC9537108 DOI: 10.1038/s41567-022-01699-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/29/2022] [Indexed: 05/16/2023]
Abstract
Cooper pairs in non-centrosymmetric superconductors can acquire finite centre-of-mass momentum in the presence of an external magnetic field. Recent theory predicts that such finite-momentum pairing can lead to an asymmetric critical current, where a dissipationless supercurrent can flow along one direction but not in the opposite one. Here we report the discovery of a giant Josephson diode effect in Josephson junctions formed from a type-II Dirac semimetal, NiTe2. A distinguishing feature is that the asymmetry in the critical current depends sensitively on the magnitude and direction of an applied magnetic field and achieves its maximum value when the magnetic field is perpendicular to the current and is of the order of just 10 mT. Moreover, the asymmetry changes sign several times with an increasing field. These characteristic features are accounted for by a model based on finite-momentum Cooper pairing that largely originates from the Zeeman shift of spin-helical topological surface states. The finite pairing momentum is further established, and its value determined, from the evolution of the interference pattern under an in-plane magnetic field. The observed giant magnitude of the asymmetry in critical current and the clear exposition of its underlying mechanism paves the way to build novel superconducting computing devices using the Josephson diode effect.
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Affiliation(s)
- Banabir Pal
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | | | | | - Margarita Davydova
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Ajesh K. Gopi
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | | | - Jonas A. Krieger
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Yang Zhang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Mihir Date
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Sailong Ju
- Swiss Light Source, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Noah Yuan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | | | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
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4
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Schuwalow S, Schröter NBM, Gukelberger J, Thomas C, Strocov V, Gamble J, Chikina A, Caputo M, Krieger J, Gardner GC, Troyer M, Aeppli G, Manfra MJ, Krogstrup P. Band Structure Extraction at Hybrid Narrow-Gap Semiconductor-Metal Interfaces. Adv Sci (Weinh) 2021; 8:2003087. [PMID: 33643798 PMCID: PMC7887586 DOI: 10.1002/advs.202003087] [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: 08/12/2020] [Revised: 10/07/2020] [Indexed: 06/12/2023]
Abstract
The design of epitaxial semiconductor-superconductor and semiconductor-metal quantum devices requires a detailed understanding of the interfacial electronic band structure. However, the band alignment of buried interfaces is difficult to predict theoretically and to measure experimentally. This work presents a procedure that allows to reliably determine critical parameters for engineering quantum devices; band offset, band bending profile, and number of occupied quantum well subbands of interfacial accumulation layers at semiconductor-metal interfaces. Soft X-ray angle-resolved photoemission is used to directly measure the quantum well states as well as valence bands and core levels for the InAs(100)/Al interface, an important platform for Majorana-zero-mode based topological qubits, and demonstrate that the fabrication process strongly influences the band offset, which in turn controls the topological phase diagrams. Since the method is transferable to other narrow gap semiconductors, it can be used more generally for engineering semiconductor-metal and semiconductor-superconductor interfaces in gate-tunable superconducting devices.
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Affiliation(s)
- Sergej Schuwalow
- Center for Quantum DevicesNiels Bohr InstituteUniversity of Copenhagen and Microsoft Quantum Materials Lab CopenhagenLyngbyDenmark
| | | | | | - Candice Thomas
- Microsoft Station Q PurdueBirck Nanotechnology CenterPurdue UniversityWest LafayetteIN47907USA
- Department of Physics and AstronomyPurdue UniversityWest LafayetteIN47907USA
| | - Vladimir Strocov
- Paul Scherrer InstitutSwiss Light SourcePSIVilligenCH‐5232Switzerland
| | - John Gamble
- Microsoft QuantumOne Microsoft WayRedmondWA98052USA
| | - Alla Chikina
- Paul Scherrer InstitutSwiss Light SourcePSIVilligenCH‐5232Switzerland
| | - Marco Caputo
- Paul Scherrer InstitutSwiss Light SourcePSIVilligenCH‐5232Switzerland
| | - Jonas Krieger
- Paul Scherrer InstitutSwiss Light SourcePSIVilligenCH‐5232Switzerland
| | - Geoffrey C. Gardner
- Microsoft Station Q PurdueBirck Nanotechnology CenterPurdue UniversityWest LafayetteIN47907USA
| | | | - Gabriel Aeppli
- Paul Scherrer InstitutSwiss Light SourcePSIVilligenCH‐5232Switzerland
- Physics DepartmentETHZurichCH‐8093Switzerland
- Institut de PhysiqueEPFLLausanneCH‐1015Switzerland
| | - Michael J. Manfra
- Microsoft Station Q PurdueBirck Nanotechnology CenterPurdue UniversityWest LafayetteIN47907USA
- Department of Physics and AstronomyPurdue UniversityWest LafayetteIN47907USA
- School of Electrical and Computer Engineering and School of Materials EngineeringPurdue UniversityWest LafayetteIN47907USA
| | - Peter Krogstrup
- Center for Quantum DevicesNiels Bohr InstituteUniversity of Copenhagen and Microsoft Quantum Materials Lab CopenhagenLyngbyDenmark
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5
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Schröter NBM, Robredo I, Klemenz S, Kirby RJ, Krieger JA, Pei D, Yu T, Stolz S, Schmitt T, Dudin P, Kim TK, Cacho C, Schnyder A, Bergara A, Strocov VN, de Juan F, Vergniory MG, Schoop LM. Weyl fermions, Fermi arcs, and minority-spin carriers in ferromagnetic CoS 2. Sci Adv 2020; 6:6/51/eabd5000. [PMID: 33355138 DOI: 10.1126/sciadv.abd5000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
Magnetic Weyl semimetals are a newly discovered class of topological materials that may serve as a platform for exotic phenomena, such as axion insulators or the quantum anomalous Hall effect. Here, we use angle-resolved photoelectron spectroscopy and ab initio calculations to discover Weyl cones in CoS2, a ferromagnet with pyrite structure that has been long studied as a candidate for half-metallicity, which makes it an attractive material for spintronic devices. We directly observe the topological Fermi arc surface states that link the Weyl nodes, which will influence the performance of CoS2 as a spin injector by modifying its spin polarization at interfaces. In addition, we directly observe a minority-spin bulk electron pocket in the corner of the Brillouin zone, which proves that CoS2 cannot be a true half-metal.
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Affiliation(s)
- Niels B M Schröter
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
| | - Iñigo Robredo
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain
- Condensed Matter Physics Department, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
| | - Sebastian Klemenz
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA
| | - Robert J Kirby
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA
| | - Jonas A Krieger
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Laboratorium für Festkörperphysik, ETH Zurich, CH-8093 Zurich, Switzerland
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Ding Pei
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Tianlun Yu
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Advanced Materials Laboratory, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Samuel Stolz
- EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Condensed Matter Physics, Station 3, EPFL, 1015 Lausanne, Switzerland
| | - Thorsten Schmitt
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | | | | | | | - Andreas Schnyder
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
| | - Aitor Bergara
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain
- Condensed Matter Physics Department, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
- Centro de Física de Materiales, Centro Mixto CSIC -UPV/EHU, 20018 Donostia, Spain
| | - Vladimir N Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Fernando de Juan
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - Maia G Vergniory
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain.
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - Leslie M Schoop
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA.
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6
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Sessi P, Fan FR, Küster F, Manna K, Schröter NBM, Ji JR, Stolz S, Krieger JA, Pei D, Kim TK, Dudin P, Cacho C, Widmer R, Borrmann H, Shi W, Chang K, Sun Y, Felser C, Parkin SSP. Handedness-dependent quasiparticle interference in the two enantiomers of the topological chiral semimetal PdGa. Nat Commun 2020; 11:3507. [PMID: 32665572 PMCID: PMC7360625 DOI: 10.1038/s41467-020-17261-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 06/16/2020] [Indexed: 11/25/2022] Open
Abstract
It has recently been proposed that combining chirality with topological band theory results in a totally new class of fermions. Understanding how these unconventional quasiparticles propagate and interact remains largely unexplored so far. Here, we use scanning tunneling microscopy to visualize the electronic properties of the prototypical chiral topological semimetal PdGa. We reveal chiral quantum interference patterns of opposite spiraling directions for the two PdGa enantiomers, a direct manifestation of the change of sign of their Chern number. Additionally, we demonstrate that PdGa remains topologically non-trivial over a large energy range, experimentally detecting Fermi arcs in an energy window of more than 1.6 eV that is symmetrically centered around the Fermi level. These results are a consequence of the deep connection between chirality in real and reciprocal space in this class of materials, and, thereby, establish PdGa as an ideal topological chiral semimetal.
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Affiliation(s)
- Paolo Sessi
- Max Planck Institute of Microstructure Physics, Halle, 06120, Germany.
| | - Feng-Ren Fan
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Felix Küster
- Max Planck Institute of Microstructure Physics, Halle, 06120, Germany
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Niels B M Schröter
- Swiss Light Source, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Jing-Rong Ji
- Max Planck Institute of Microstructure Physics, Halle, 06120, Germany
| | - Samuel Stolz
- EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600, Dübendorf, Switzerland
- Institute of Condensed Matter Physics, Station 3, EPFL, 1015, Lausanne, Switzerland
| | - Jonas A Krieger
- Swiss Light Source, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
- Laboratorium für Festkörperphysik, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Ding Pei
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom
| | - Timur K Kim
- Diamond Light Source, Didcot, OX110DE, United Kingdom
| | - Pavel Dudin
- Diamond Light Source, Didcot, OX110DE, United Kingdom
| | - Cephise Cacho
- Diamond Light Source, Didcot, OX110DE, United Kingdom
| | - Roland Widmer
- EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600, Dübendorf, Switzerland
| | - Horst Borrmann
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Wujun Shi
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201203, China
| | - Kai Chang
- Max Planck Institute of Microstructure Physics, Halle, 06120, Germany
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Yan Sun
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Halle, 06120, Germany.
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7
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Schröter NBM, Stolz S, Manna K, de Juan F, Vergniory MG, Krieger JA, Pei D, Schmitt T, Dudin P, Kim TK, Cacho C, Bradlyn B, Borrmann H, Schmidt M, Widmer R, Strocov VN, Felser C. Observation and control of maximal Chern numbers in a chiral topological semimetal. Science 2020; 369:179-183. [DOI: 10.1126/science.aaz3480] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 05/07/2020] [Indexed: 11/02/2022]
Abstract
Topological semimetals feature protected nodal band degeneracies characterized by a topological invariant known as the Chern number (C). Nodal band crossings with linear dispersion are expected to have at most |C|=4, which sets an upper limit to the magnitude of many topological phenomena in these materials. Here, we show that the chiral crystal palladium gallium (PdGa) displays multifold band crossings, which are connected by exactly four surface Fermi arcs, thus proving that they carry the maximal Chern number magnitude of 4. By comparing two enantiomers, we observe a reversal of their Fermi-arc velocities, which demonstrates that the handedness of chiral crystals can be used to control the sign of their Chern numbers.
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Affiliation(s)
| | - Samuel Stolz
- EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Condensed Matter Physics, Station 3, EPFL, 1015 Lausanne, Switzerland
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - Fernando de Juan
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - Maia G. Vergniory
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - Jonas A. Krieger
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Laboratorium für Festkörperphysik, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Ding Pei
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Thorsten Schmitt
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | | | | | | | - Barry Bradlyn
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3080, USA
| | - Horst Borrmann
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - Marcus Schmidt
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - Roland Widmer
- EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Vladimir N. Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
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8
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Kumar N, Yao M, Nayak J, Vergniory MG, Bannies J, Wang Z, Schröter NBM, Strocov VN, Müchler L, Shi W, Rienks EDL, Mañes JL, Shekhar C, Parkin SSP, Fink J, Fecher GH, Sun Y, Bernevig BA, Felser C. Signatures of Sixfold Degenerate Exotic Fermions in a Superconducting Metal PdSb 2. Adv Mater 2020; 32:e1906046. [PMID: 32037624 DOI: 10.1002/adma.201906046] [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] [Received: 09/15/2019] [Revised: 12/24/2019] [Indexed: 06/10/2023]
Abstract
Multifold degenerate points in the electronic structure of metals lead to exotic behaviors. These range from twofold and fourfold degenerate Weyl and Dirac points, respectively, to sixfold and eightfold degenerate points that are predicted to give rise, under modest magnetic fields or strain, to topological semimetallic behaviors. The present study shows that the nonsymmorphic compound PdSb2 hosts six-component fermions or sextuplets. Using angle-resolved photoemission spectroscopy, crossing points formed by three twofold degenerate parabolic bands are directly observed at the corner of the Brillouin zone. The group theory analysis proves that under weak spin-orbit interaction, a band inversion occurs.
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Affiliation(s)
- Nitesh Kumar
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Mengyu Yao
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Jayita Nayak
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Maia G Vergniory
- Donostian International Physics Center, Paseo Manuel de Lardizabal 4, 20018, San Sebastian, Spain
- KERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013, Bilbao, Spain
| | - Jörn Bannies
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Zhijun Wang
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | | | | | - Lukas Müchler
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, 10010, USA
| | - Wujun Shi
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Emile D L Rienks
- Leibniz Institut für Festkörper und Werkstoffforschung IFW Dresden, Helmholtzstrasse 20, 01171, Dresden, Germany
- Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, 01062, Dresden, Germany
| | - J L Mañes
- Condensed Matter Physics Department, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Apdo. 644, 48080, Bilbao, Spain
| | - Chandra Shekhar
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, 06120, Halle, Germany
| | - Jörg Fink
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
- Leibniz Institut für Festkörper und Werkstoffforschung IFW Dresden, Helmholtzstrasse 20, 01171, Dresden, Germany
- Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, 01062, Dresden, Germany
| | - Gerhard H Fecher
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Yan Sun
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - B Andrei Bernevig
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
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9
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Puppin M, Deng Y, Nicholson CW, Feldl J, Schröter NBM, Vita H, Kirchmann PS, Monney C, Rettig L, Wolf M, Ernstorfer R. Time- and angle-resolved photoemission spectroscopy of solids in the extreme ultraviolet at 500 kHz repetition rate. Rev Sci Instrum 2019; 90:023104. [PMID: 30831759 DOI: 10.1063/1.5081938] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 01/21/2019] [Indexed: 06/09/2023]
Abstract
Time- and angle-resolved photoemission spectroscopy (trARPES) employing a 500 kHz extreme-ultraviolet light source operating at 21.7 eV probe photon energy is reported. Based on a high-power ytterbium laser, optical parametric chirped pulse amplification, and ultraviolet-driven high-harmonic generation, the light source produces an isolated high-harmonic with 110 meV bandwidth and a flux of more than 1011 photons/s on the sample. Combined with a state-of-the-art ARPES chamber, this table-top experiment allows high-repetition rate pump-probe experiments of electron dynamics in occupied and normally unoccupied (excited) states in the entire Brillouin zone and with a temporal system response function below 40 fs.
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Affiliation(s)
- M Puppin
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Y Deng
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - C W Nicholson
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - J Feldl
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - N B M Schröter
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - H Vita
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - P S Kirchmann
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - C Monney
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - L Rettig
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - M Wolf
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - R Ernstorfer
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
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10
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Chen C, Wang M, Wu J, Fu H, Yang H, Tian Z, Tu T, Peng H, Sun Y, Xu X, Jiang J, Schröter NBM, Li Y, Pei D, Liu S, Ekahana SA, Yuan H, Xue J, Li G, Jia J, Liu Z, Yan B, Peng H, Chen Y. Electronic structures and unusually robust bandgap in an ultrahigh-mobility layered oxide semiconductor, Bi 2O 2Se. Sci Adv 2018; 4:eaat8355. [PMID: 30225369 PMCID: PMC6140625 DOI: 10.1126/sciadv.aat8355] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/07/2018] [Indexed: 05/07/2023]
Abstract
Semiconductors are essential materials that affect our everyday life in the modern world. Two-dimensional semiconductors with high mobility and moderate bandgap are particularly attractive today because of their potential application in fast, low-power, and ultrasmall/thin electronic devices. We investigate the electronic structures of a new layered air-stable oxide semiconductor, Bi2O2Se, with ultrahigh mobility (~2.8 × 105 cm2/V⋅s at 2.0 K) and moderate bandgap (~0.8 eV). Combining angle-resolved photoemission spectroscopy and scanning tunneling microscopy, we mapped out the complete band structures of Bi2O2Se with key parameters (for example, effective mass, Fermi velocity, and bandgap). The unusual spatial uniformity of the bandgap without undesired in-gap states on the sample surface with up to ~50% defects makes Bi2O2Se an ideal semiconductor for future electronic applications. In addition, the structural compatibility between Bi2O2Se and interesting perovskite oxides (for example, cuprate high-transition temperature superconductors and commonly used substrate material SrTiO3) further makes heterostructures between Bi2O2Se and these oxides possible platforms for realizing novel physical phenomena, such as topological superconductivity, Josephson junction field-effect transistor, new superconducting optoelectronics, and novel lasers.
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Affiliation(s)
- Cheng Chen
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Meixiao Wang
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | - Jinxiong Wu
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Huixia Fu
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Haifeng Yang
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | - Zhen Tian
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | - Teng Tu
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Han Peng
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Yan Sun
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
| | - Xiang Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People’s Republic of China
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Juan Jiang
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Niels B. M. Schröter
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Yiwei Li
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Ding Pei
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Shuai Liu
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | | | - Hongtao Yuan
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Jiamin Xue
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | - Gang Li
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | - Jinfeng Jia
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hailin Peng
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
- Corresponding author. (Y.C.); (Hailin Peng)
| | - Yulin Chen
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- School of Physical Science and Technology, ShanghaiTech University and Chinese Academy of Sciences–Shanghai Science Research Center, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People’s Republic of China
- Corresponding author. (Y.C.); (Hailin Peng)
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11
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Horio M, Hauser K, Sassa Y, Mingazheva Z, Sutter D, Kramer K, Cook A, Nocerino E, Forslund OK, Tjernberg O, Kobayashi M, Chikina A, Schröter NBM, Krieger JA, Schmitt T, Strocov VN, Pyon S, Takayama T, Takagi H, Lipscombe OJ, Hayden SM, Ishikado M, Eisaki H, Neupert T, Månsson M, Matt CE, Chang J. Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates. Phys Rev Lett 2018; 121:077004. [PMID: 30169083 DOI: 10.1103/physrevlett.121.077004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Indexed: 06/08/2023]
Abstract
We present a soft x-ray angle-resolved photoemission spectroscopy study of overdoped high-temperature superconductors. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No k_{z} dispersion is observed along the nodal direction, whereas a significant antinodal k_{z} dispersion is identified for La-based cuprates. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La_{2-x}Sr_{x}CuO_{4} cannot be assigned to the van Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat.
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Affiliation(s)
- M Horio
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - K Hauser
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Y Sassa
- Department of Physics and Astronomy, Uppsala University, SE-75121 Uppsala, Sweden
| | - Z Mingazheva
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - D Sutter
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - K Kramer
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - A Cook
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - E Nocerino
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - O K Forslund
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - O Tjernberg
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - M Kobayashi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Chikina
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - N B M Schröter
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J A Krieger
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Laboratorium für Festkörperphysik, ETH Zürich, CH-8093 Zürich, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Pyon
- Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
| | - T Takayama
- Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
| | - H Takagi
- Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
| | - O J Lipscombe
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - S M Hayden
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - M Ishikado
- Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan
| | - H Eisaki
- Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan
| | - T Neupert
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - M Månsson
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - C E Matt
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - J Chang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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12
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Peng H, Schröter NBM, Yin J, Wang H, Chung TF, Yang H, Ekahana S, Liu Z, Jiang J, Yang L, Zhang T, Chen C, Ni H, Barinov A, Chen YP, Liu Z, Peng H, Chen Y. Substrate Doping Effect and Unusually Large Angle van Hove Singularity Evolution in Twisted Bi- and Multilayer Graphene. Adv Mater 2017; 29:1606741. [PMID: 28481053 DOI: 10.1002/adma.201606741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/22/2017] [Indexed: 06/07/2023]
Abstract
Graphene has demonstrated great potential in new-generation electronic applications due to its unique electronic properties such as large carrier Fermi velocity, ultrahigh carrier mobility, and high material stability. Interestingly, the electronic structures can be further engineered in multilayer graphene by the introduction of a twist angle between different layers to create van Hove singularities (vHSs) at adjustable binding energy. In this work, using angle-resolved photoemission spectroscopy with sub-micrometer spatial resolution, the band structures and their evolution are systematically studied with twist angle in bilayer and trilayer graphene sheets. A doping effect is directly observed in graphene multilayer system as well as vHSs in bilayer graphene over a wide range of twist angles (from 5° to 31°) with wide tunable energy range over 2 eV. In addition, the formation of multiple vHSs (at different binding energies) is also observed in trilayer graphene. The large tuning range of vHS binding energy in twisted multilayer graphene provides a promising material base for optoelectrical applications with broadband wavelength selectivity from the infrared to the ultraviolet regime, as demonstrated by an example application of wavelength selective photodetector.
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Affiliation(s)
- Han Peng
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Niels B M Schröter
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Jianbo Yin
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Huan Wang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Ting-Fung Chung
- Department of Physics and Astronomy, Birck Nanotechnology Center, and School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Haifeng Yang
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, China
| | - Sandy Ekahana
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, China
| | - Juan Jiang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Collaborative Innovation Center of Quantum Matter and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Teng Zhang
- State Key Laboratory of Low Dimensional Quantum Physics, Collaborative Innovation Center of Quantum Matter and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Cheng Chen
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Heng Ni
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | | | - Yong P Chen
- Department of Physics and Astronomy, Birck Nanotechnology Center, and School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhongfan Liu
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Hailin Peng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Yulin Chen
- Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, China
- State Key Laboratory of Low Dimensional Quantum Physics, Collaborative Innovation Center of Quantum Matter and Department of Physics, Tsinghua University, Beijing, 100084, China
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