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Dai J, Frantzeskakis E, Aryal N, Chen KW, Fortuna F, Rault JE, Le Fèvre P, Balicas L, Miyamoto K, Okuda T, Manousakis E, Baumbach RE, Santander-Syro AF. Experimental Observation and Spin Texture of Dirac Node Arcs in Tetradymite Topological Metals. Phys Rev Lett 2021; 126:196407. [PMID: 34047592 DOI: 10.1103/physrevlett.126.196407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/08/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
We report the observation of a nontrivial spin texture in Dirac node arcs, i.e., novel topological objects formed when Dirac cones of massless particles extend along an open one-dimensional line in momentum space. We find that such states are present in all the compounds of the tetradymite M_{2}Te_{2}X family (M=Ti, Zr, or Hf and X=P or As) regardless of the weak or strong character of the topological invariant. The Dirac node arcs in tetradymites are thus the simplest possible textbook example of a type-I Dirac system with a single spin-polarized node arc.
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Affiliation(s)
- J Dai
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - E Frantzeskakis
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - N Aryal
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - K-W Chen
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - F Fortuna
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - J E Rault
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - P Le Fèvre
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - L Balicas
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - K Miyamoto
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - T Okuda
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - E Manousakis
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, National and Kapodistrian University of Athens, Panepistimioupolis, Zografos, 157 84 Athens, Greece
| | - R E Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - A F Santander-Syro
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
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Usachov DY, Nechaev IA, Poelchen G, Güttler M, Krasovskii EE, Schulz S, Generalov A, Kliemt K, Kraiker A, Krellner C, Kummer K, Danzenbächer S, Laubschat C, Weber AP, Sánchez-Barriga J, Chulkov EV, Santander-Syro AF, Imai T, Miyamoto K, Okuda T, Vyalikh DV. Cubic Rashba Effect in the Surface Spin Structure of Rare-Earth Ternary Materials. Phys Rev Lett 2020; 124:237202. [PMID: 32603174 DOI: 10.1103/physrevlett.124.237202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/13/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Spin-orbit interaction and structure inversion asymmetry in combination with magnetic ordering is a promising route to novel materials with highly mobile spin-polarized carriers at the surface. Spin-resolved measurements of the photoemission current from the Si-terminated surface of the antiferromagnet TbRh_{2}Si_{2} and their analysis within an ab initio one-step theory unveil an unusual triple winding of the electron spin along the fourfold-symmetric constant energy contours of the surface states. A two-band k·p model is presented that yields the triple winding as a cubic Rashba effect. The curious in-plane spin-momentum locking is remarkably robust and remains intact across a paramagnetic-antiferromagnetic transition in spite of spin-orbit interaction on Rh atoms being considerably weaker than the out-of-plane exchange field due to the Tb 4f moments.
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Affiliation(s)
- D Yu Usachov
- St. Petersburg State University, 7/9 Universitetskaya Naberezhnaya, St. Petersburg, 199034, Russia
| | - I A Nechaev
- Department of Electricity and Electronics, FCT-ZTF, UPV-EHU, 48080 Bilbao, Spain
| | - G Poelchen
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - M Güttler
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - E E Krasovskii
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia/San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
| | - S Schulz
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - A Generalov
- Max IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden
| | - K Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - A Kraiker
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - K Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, France
| | - S Danzenbächer
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - C Laubschat
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - A P Weber
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - E V Chulkov
- St. Petersburg State University, 7/9 Universitetskaya Naberezhnaya, St. Petersburg, 199034, Russia
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia/San Sebastián, Basque Country, Spain
- Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20018 Donostia/San Sebastián, Basque Country, Spain
- Tomsk State University, Lenina Avenue 36, 634050, Tomsk, Russia
| | - A F Santander-Syro
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
| | - T Imai
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - K Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - T Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
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Taniuchi T, Motoyui Y, Morozumi K, Rödel TC, Fortuna F, Santander-Syro AF, Shin S. Imaging of room-temperature ferromagnetic nano-domains at the surface of a non-magnetic oxide. Nat Commun 2016; 7:11781. [PMID: 27283225 PMCID: PMC4906390 DOI: 10.1038/ncomms11781] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 04/28/2016] [Indexed: 12/03/2022] Open
Abstract
Two-dimensional electron gases at oxide surfaces or interfaces show exotic ordered states of matter, like superconductivity, magnetism or spin-polarized states, and are a promising platform for alternative oxide-based electronics. Here we directly image a dense population of randomly distributed ferromagnetic domains of ∼40 nm typical sizes at room temperature at the oxygen-deficient surface of SrTiO3, a non-magnetic transparent insulator in the bulk. We use laser-based photoemission electron microscopy, an experimental technique that gives selective spin detection of the surface carriers, even in bulk insulators, with a high spatial resolution of 2.6 nm. We furthermore find that the Curie temperature in this system is as high as 900 K. These findings open perspectives for applications in nano-domain magnetism and spintronics using oxide-based devices, for instance through the nano-engineering of oxygen vacancies at surfaces or interfaces of transition-metal oxides. The surfaces of transition metal oxides exhibit a wide range of functional behaviours, from magnetism to superconductivity. Here, the authors use high-resolution microscopy to image the temperature dependent development of nanoscale ferromagnetic domains on an oxygen-deficient SrTiO3 surface.
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Affiliation(s)
- T Taniuchi
- Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan.,CREST, Japan Science and Technology Agency, Tokyo 102-0075, Japan
| | - Y Motoyui
- Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan
| | - K Morozumi
- Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan
| | - T C Rödel
- CSNSM, CNRS/IN2P3 and Université Paris-Sud, Bâtiments 104 et 108, Orsay 91405, France.,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, Gif-sur-Yvette 91192, France
| | - F Fortuna
- CSNSM, CNRS/IN2P3 and Université Paris-Sud, Bâtiments 104 et 108, Orsay 91405, France
| | - A F Santander-Syro
- CSNSM, CNRS/IN2P3 and Université Paris-Sud, Bâtiments 104 et 108, Orsay 91405, France
| | - S Shin
- Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan.,CREST, Japan Science and Technology Agency, Tokyo 102-0075, Japan
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Santander-Syro AF, Fortuna F, Bareille C, Rödel TC, Landolt G, Plumb NC, Dil JH, Radović M. Giant spin splitting of the two-dimensional electron gas at the surface of SrTiO3. Nat Mater 2014; 13:1085-1090. [PMID: 25306421 DOI: 10.1038/nmat4107] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
Two-dimensional electron gases (2DEGs) forming at the interfaces of transition metal oxides exhibit a range of properties, including tunable insulator-superconductor-metal transitions, large magnetoresistance, coexisting ferromagnetism and superconductivity, and a spin splitting of a few meV (refs 10, 11). Strontium titanate (SrTiO3), the cornerstone of such oxide-based electronics, is a transparent, non-magnetic, wide-bandgap insulator in the bulk, and has recently been found to host a surface 2DEG (refs 12-15). The most strongly confined carriers within this 2DEG comprise two subbands, separated by an energy gap of 90 meV and forming concentric circular Fermi surfaces. Using spin- and angle-resolved photoemission spectroscopy (SARPES), we show that the electron spins in these subbands have opposite chiralities. Although the Rashba effect might be expected to give rise to such spin textures, the giant splitting of almost 100 meV at the Fermi level is far larger than anticipated. Moreover, in contrast to a simple Rashba system, the spin-polarized subbands are non-degenerate at the Brillouin zone centre. This degeneracy can be lifted by time-reversal symmetry breaking, implying the possible existence of magnetic order. These results show that confined electronic states at oxide surfaces can be endowed with novel, non-trivial properties that are both theoretically challenging to anticipate and promising for technological applications.
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Affiliation(s)
- A F Santander-Syro
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
| | - F Fortuna
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
| | - C Bareille
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
| | - T C Rödel
- 1] CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France [2] Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - G Landolt
- 1] Physik-Institut, Universität Zürich, Winterthurerstrasse 190 8057 Zürich, Switzerland [2] Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J H Dil
- 1] Physik-Institut, Universität Zürich, Winterthurerstrasse 190 8057 Zürich, Switzerland [2] Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland [3] Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Radović
- 1] Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland [2] Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland [3] SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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Bareille C, Fortuna F, Rödel TC, Bertran F, Gabay M, Cubelos OH, Taleb-Ibrahimi A, Le Fèvre P, Bibes M, Barthélémy A, Maroutian T, Lecoeur P, Rozenberg MJ, Santander-Syro AF. Two-dimensional electron gas with six-fold symmetry at the (111) surface of KTaO3. Sci Rep 2014; 4:3586. [PMID: 24394996 PMCID: PMC3882744 DOI: 10.1038/srep03586] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 12/03/2013] [Indexed: 11/09/2022] Open
Abstract
Two-dimensional electron gases (2DEGs) at transition-metal oxide (TMO) interfaces, and boundary states in topological insulators, are being intensively investigated. The former system harbors superconductivity, large magneto-resistance, and ferromagnetism. In the latter, honeycomb-lattice geometry plus bulk spin-orbit interactions lead to topologically protected spin-polarized bands. 2DEGs in TMOs with a honeycomb-like structure could yield new states of matter, but they had not been experimentally realized, yet. We successfully created a 2DEG at the (111) surface of KTaO3, a strong insulator with large spin-orbit coupling. Its confined states form a network of weakly-dispersing electronic gutters with 6-fold symmetry, a topology novel to all known oxide-based 2DEGs. If those pertain to just one Ta-(111) bilayer, model calculations predict that it can be a topological metal. Our findings demonstrate that completely new electronic states, with symmetries not realized in the bulk, can be tailored in oxide surfaces, promising for TMO-based devices.
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Affiliation(s)
- C. Bareille
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
| | - F. Fortuna
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
| | - T. C. Rödel
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
- Universität Würzburg, Experimentelle Physik VII, Am Hubland, 97074 Würzburg, Germany
| | - F. Bertran
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - M. Gabay
- Laboratoire de Physique des Solides, Université Paris-Sud and CNRS, Bâtiment 510, 91405 Orsay, France
| | - O. Hijano Cubelos
- Laboratoire de Physique des Solides, Université Paris-Sud and CNRS, Bâtiment 510, 91405 Orsay, France
| | - A. Taleb-Ibrahimi
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - P. Le Fèvre
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - M. Bibes
- Unité Mixte de Physique CNRS/Thales, Campus de l'Ecole Polytechnique, 1 Av. A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - A. Barthélémy
- Unité Mixte de Physique CNRS/Thales, Campus de l'Ecole Polytechnique, 1 Av. A. Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - T. Maroutian
- Institut d'Electronique Fondamentale, Université Paris-Sud and CNRS, Bâtiment 220, 91405 Orsay, France
| | - P. Lecoeur
- Institut d'Electronique Fondamentale, Université Paris-Sud and CNRS, Bâtiment 220, 91405 Orsay, France
| | - M. J. Rozenberg
- Laboratoire de Physique des Solides, Université Paris-Sud and CNRS, Bâtiment 510, 91405 Orsay, France
| | - A. F. Santander-Syro
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay cedex, France
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Boariu FL, Bareille C, Schwab H, Nuber A, Lejay P, Durakiewicz T, Reinert F, Santander-Syro AF. Momentum-resolved evolution of the Kondo lattice into "hidden order" in URu2Si2. Phys Rev Lett 2013; 110:156404. [PMID: 25167291 DOI: 10.1103/physrevlett.110.156404] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Indexed: 06/03/2023]
Abstract
We study, using high-resolution angle-resolved photoemission spectroscopy, the evolution of the electronic structure in URu2Si2 at the Γ, Z, and X high-symmetry points from the high-temperature Kondo-screened regime to the low-temperature hidden-order (HO) state. At all temperatures and symmetry points, we find structures resulting from the interaction between heavy and light bands related to the Kondo-lattice formation. At the X point, we directly measure a hybridization gap of 11 meV already open at temperatures above the ordered phase. Strikingly, we find that while the HO induces pronounced changes at Γ and Z, the hybridization gap at X does not change, indicating that the hidden-order parameter is anisotropic. Furthermore, at the Γ and Z points, we observe the opening of a gap in momentum in the HO state, and show that the associated electronic structure results from the hybridization of a light electron band with the Kondo-lattice bands characterizing the paramagnetic state.
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Affiliation(s)
- F L Boariu
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - C Bareille
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay Cedex, France
| | - H Schwab
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - A Nuber
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - P Lejay
- Institut Néel, CNRS/UJF, B.P. 166, 38042 Grenoble Cedex 9, France
| | - T Durakiewicz
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - F Reinert
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany and Karlsruher Institut für Technologie (KIT), Gemeinschaftslabor für Nanoanalythik, D-76021 Karlsruhe, Germany
| | - A F Santander-Syro
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay Cedex, France
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Santander-Syro AF, Ikeda M, Yoshida T, Fujimori A, Ishizaka K, Okawa M, Shin S, Liang B, Zimmers A, Greene RL, Bontemps N. Two-Fermi-surface superconducting state and a nodal d-wave energy gap of the electron-doped Sm1.85Ce0.15CuO(4-δ) cuprate superconductor. Phys Rev Lett 2011; 106:197002. [PMID: 21668192 DOI: 10.1103/physrevlett.106.197002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Indexed: 05/30/2023]
Abstract
We report on laser-excited angle-resolved photoemission spectroscopy in the electron-doped cuprate Sm1.85Ce0.15CuO(4-δ). The data show the existence of a nodal hole-pocket Fermi surface both in the normal and superconducting states. We prove that its origin is long-range antiferromagnetism by an analysis of the coherence factors in the main and folded bands. This coexistence of long-range antiferrmagnetism and superconductivity implies that electron-doped cuprates are two-Fermi-surface superconductors. The measured superconducting gap in the nodal hole pocket is compatible with a d-wave symmetry.
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Liu C, Samolyuk GD, Lee Y, Ni N, Kondo T, Santander-Syro AF, Bud'ko SL, McChesney JL, Rotenberg E, Valla T, Fedorov AV, Canfield PC, Harmon BN, Kaminski A. K-doping dependence of the Fermi surface of the iron-arsenic Ba1-xKxFe2As2 superconductor using angle-resolved photoemission spectroscopy. Phys Rev Lett 2008; 101:177005. [PMID: 18999778 DOI: 10.1103/physrevlett.101.177005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Indexed: 05/27/2023]
Abstract
We use angle-resolved photoemission spectroscopy to investigate the electronic properties of the newly discovered iron-arsenic superconductor Ba_(1-x)K_(x)Fe_(2)As_(2) and nonsuperconducting BaFe_(2)As_(2). Our study indicates that the Fermi surface of the undoped, parent compound BaFe_(2)As_(2) consists of hole pocket(s) at Gamma (0,0) and larger electron pocket(s) at X (1,0), in general agreement with full-potential linearized plane wave calculations. Upon doping with potassium, the hole pocket expands and the electron pocket becomes smaller with its bottom approaching the chemical potential. Such an evolution of the Fermi surface is consistent with hole doping within a rigid-band shift model. Our results also indicate that the full-potential linearized plane wave calculation is a reasonable approach for modeling the electronic properties of both undoped and K-doped iron arsenites.
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Affiliation(s)
- Chang Liu
- Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
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9
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Kondo T, Santander-Syro AF, Copie O, Liu C, Tillman ME, Mun ED, Schmalian J, Bud'ko SL, Tanatar MA, Canfield PC, Kaminski A. Momentum dependence of the superconducting gap in NdFeAsO0.9F0.1 single crystals measured by angle resolved photoemission spectroscopy. Phys Rev Lett 2008; 101:147003. [PMID: 18851561 DOI: 10.1103/physrevlett.101.147003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2008] [Indexed: 05/26/2023]
Abstract
We use angle resolved photoemission spectroscopy to study the momentum dependence of the superconducting gap in NdFeAsO0.9F0.1 single crystals. We find that the Gamma hole pocket is fully gapped below the superconducting transition temperature. The value of the superconducting gap is 15+/-1.5 meV and its anisotropy around the hole pocket is smaller than 20% of this value-consistent with an isotropic or anisotropic s-wave symmetry of the order parameter. This is a significant departure from the situation in the cuprates, pointing to the possibility that the superconductivity in the iron arsenic based system arises from a different mechanism.
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Affiliation(s)
- Takeshi Kondo
- Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
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10
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Santander-Syro AF, Lobo RPSM, Bontemps N, Konstantinovic Z, Li Z, Raffy H. Absence of a loss of in-plane infrared spectral weight in the pseudogap regime of Bi(2)Sr(2)CaCu(2)O(8+delta). Phys Rev Lett 2002; 88:097005. [PMID: 11864047 DOI: 10.1103/physrevlett.88.097005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2001] [Indexed: 05/23/2023]
Abstract
The ab-plane reflectance of Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi-2212) thin films was measured in the 30-25 000 cm(-1) range for one underdoped ( T(c) = 70 K), and one overdoped sample ( T(c) = 63 K) down to 10 K. We find similar behaviors in the temperature dependence of the normal-state infrared response of both samples. Above T(c), the effective spectral weight, obtained from the integrated conductivity, does not decrease when T decreases, so that no opening of an optical pseudogap is seen. We suggest that these are consequences of the pseudogap opening in the k = (0,pi) direction and of the in-plane infrared conductivity being mostly sensitive to the k = (pi,pi) direction.
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Affiliation(s)
- A F Santander-Syro
- Laboratoire de Physique du Solide, Ecole Supérieure de Physique et Chimie Industrielles de la Ville de Paris, CNRS UPR 5, 75231 Paris Cedex 5, France
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