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Drozdov IK, Pletikosić I, Kim CK, Fujita K, Gu GD, Davis JCS, Johnson PD, Božović I, Valla T. Phase diagram of Bi 2Sr 2CaCu 2O 8+δ revisited. Nat Commun 2018; 9:5210. [PMID: 30523265 PMCID: PMC6283832 DOI: 10.1038/s41467-018-07686-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [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: 06/20/2018] [Accepted: 11/12/2018] [Indexed: 11/09/2022] Open
Abstract
In cuprate superconductors, the doping of carriers into the parent Mott insulator induces superconductivity and various other phases whose characteristic temperatures are typically plotted versus the doping level p. In most materials, p cannot be determined from the chemical composition, but it is derived from the superconducting transition temperature, Tc, using the assumption that the Tc dependence on doping is universal. Here, we present angle-resolved photoemission studies of Bi2Sr2CaCu2O8+δ, cleaved and annealed in vacuum or in ozone to reduce or increase the doping from the initial value corresponding to Tc = 91 K. We show that p can be determined from the underlying Fermi surfaces and that in-situ annealing allows mapping of a wide doping regime, covering the superconducting dome and the non-superconducting phase on the overdoped side. Our results show a surprisingly smooth dependence of the inferred Fermi surface with doping. In the highly overdoped regime, the superconducting gap approaches the value of 2Δ0 = (4 ± 1)kBTc.
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Affiliation(s)
- I K Drozdov
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
| | - I Pletikosić
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - C-K Kim
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
| | - K Fujita
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
| | - J C Séamus Davis
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY, 14853, USA
| | - P D Johnson
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
| | - I Božović
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA
| | - T Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY, 11973, USA.
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Pletikosić I, von Rohr F, Pervan P, Das PK, Vobornik I, Cava RJ, Valla T. Band Structure of the IV-VI Black Phosphorus Analog and Thermoelectric SnSe. Phys Rev Lett 2018; 120:156403. [PMID: 29756873 DOI: 10.1103/physrevlett.120.156403] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/29/2017] [Indexed: 06/08/2023]
Abstract
The success of black phosphorus in fast electronic and photonic devices is hindered by its rapid degradation in the presence of oxygen. Orthorhombic tin selenide is a representative of group IV-VI binary compounds that are robust and isoelectronic and share the same structure with black phosphorus. We measure the band structure of SnSe and find highly anisotropic valence bands that form several valleys having fast dispersion within the layers and negligible dispersion across. This is exactly the band structure desired for efficient thermoelectric generation where SnSe has shown great promise.
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Affiliation(s)
- I Pletikosić
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Condensed Matter and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - F von Rohr
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - P Pervan
- Institut za fiziku, HR-10000 Zagreb, Croatia
| | - P K Das
- Istituto Officina dei Materiali (IOM-CNR), Laboratorio TASC, I-34149 Trieste, Italy
- International Centre for Theoretical Physics, I-34151 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM-CNR), Laboratorio TASC, I-34149 Trieste, Italy
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - T Valla
- Condensed Matter and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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Kushwaha SK, Pletikosić I, Liang T, Gyenis A, Lapidus SH, Tian Y, Zhao H, Burch KS, Lin J, Wang W, Ji H, Fedorov AV, Yazdani A, Ong NP, Valla T, Cava RJ. Sn-doped Bi1.1Sb0.9Te2S bulk crystal topological insulator with excellent properties. Nat Commun 2016; 7:11456. [PMID: 27118032 PMCID: PMC4853473 DOI: 10.1038/ncomms11456] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [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: 08/06/2015] [Accepted: 03/30/2016] [Indexed: 12/03/2022] Open
Abstract
A long-standing issue in topological insulator research has been to find a bulk single crystal material that provides a high-quality platform for characterizing topological surface states without interference from bulk electronic states. This material would ideally be a bulk insulator, have a surface state Dirac point energy well isolated from the bulk valence and conduction bands, display quantum oscillations from the surface state electrons and be growable as large, high-quality bulk single crystals. Here we show that this material obstacle is overcome by bulk crystals of lightly Sn-doped Bi1.1Sb0.9Te2S grown by the vertical Bridgman method. We characterize Sn-BSTS via angle-resolved photoemission spectroscopy, scanning tunnelling microscopy, transport studies, X-ray diffraction and Raman scattering. We present this material as a high-quality topological insulator that can be reliably grown as bulk single crystals and thus studied by many researchers interested in topological surface states. An ideal topological insulator possesses an insulating bulk and a unique conducting surface however such behaviour is typically inhibited by bulk conduction due to defects. Here, the authors show that Sn-doped Bi1.1Sb0.9Te2S grown by the vertical Bridgman technique might overcome this hurdle.
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Affiliation(s)
- S K Kushwaha
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - I Pletikosić
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.,Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Department, Upton, New York 11973, USA
| | - T Liang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - A Gyenis
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - S H Lapidus
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yao Tian
- Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7
| | - He Zhao
- Department of Physics, Boston College, Boston, Massachusetts 02467-3804, USA
| | - K S Burch
- Department of Physics, Boston College, Boston, Massachusetts 02467-3804, USA
| | - Jingjing Lin
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Wudi Wang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Huiwen Ji
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - A V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ali Yazdani
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - N P Ong
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - T Valla
- Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Department, Upton, New York 11973, USA
| | - R J Cava
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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Pletikosić I, Ali MN, Fedorov AV, Cava RJ, Valla T. Electronic structure basis for the extraordinary magnetoresistance in WTe2. Phys Rev Lett 2014; 113:216601. [PMID: 25479512 DOI: 10.1103/physrevlett.113.216601] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Indexed: 05/13/2023]
Abstract
The electronic structure basis of the extremely large magnetoresistance in layered nonmagnetic tungsten ditelluride has been investigated by angle-resolved photoelectron spectroscopy. Hole and electron pockets of approximately the same size were found at low temperatures, suggesting that carrier compensation should be considered the primary source of the effect. The material exhibits a highly anisotropic Fermi surface from which the pronounced anisotropy of the magnetoresistance follows. A change in the Fermi surface with temperature was found and a high-density-of-states band that may take over conduction at higher temperatures and cause the observed turn-on behavior of the magnetoresistance in WTe2 was identified.
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Affiliation(s)
- I Pletikosić
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Mazhar N Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - A V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - T Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Yilmaz T, Pletikosić I, Weber AP, Sadowski JT, Gu GD, Caruso AN, Sinkovic B, Valla T. Absence of a proximity effect for a thin-films of a Bi2Se3 topological insulator grown on top of a Bi2Sr2CaCu2O(8+δ) cuprate superconductor. Phys Rev Lett 2014; 113:067003. [PMID: 25148345 DOI: 10.1103/physrevlett.113.067003] [Citation(s) in RCA: 6] [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: 03/17/2014] [Indexed: 06/03/2023]
Abstract
Proximity-induced superconductivity in a 3D topological insulator represents a new avenue for observing zero-energy Majorana fermions inside vortex cores. Relatively small gaps and low transition temperatures of conventional s-wave superconductors put hard constraints on these experiments. Significantly larger gaps and higher transition temperatures in cuprate superconductors might be an attractive alternative to considerably relax these constraints, but it is not clear whether the proximity effect would be effective in heterostructures involving cuprates and topological insulators. Here, we present angle-resolved photoemission studies of thin Bi(2)Se(3) films grown in situ on optimally doped Bi(2)Sr(2)CaCu(2)O(8+δ) substrates that show the absence of proximity-induced gaps on the surfaces of Bi(2)Se(3) films as thin as a 1.5 quintuple layer. These results suggest that the superconducting proximity effect between a cuprate superconductor and a topological insulator is strongly suppressed, likely due to a very short coherence length along the c axis, incompatible crystal and pairing symmetries at the interface, small size of the topological surface state's Fermi surface, and adverse effects of a strong spin-orbit coupling in the topological material.
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Affiliation(s)
- T Yilmaz
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - I Pletikosić
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - A P Weber
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - J T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - A N Caruso
- Department of Physics, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA
| | - B Sinkovic
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - T Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Petrović M, Šrut Rakić I, Runte S, Busse C, Sadowski JT, Lazić P, Pletikosić I, Pan ZH, Milun M, Pervan P, Atodiresei N, Brako R, Šokčević D, Valla T, Michely T, Kralj M. The mechanism of caesium intercalation of graphene. Nat Commun 2014; 4:2772. [PMID: 24212475 DOI: 10.1038/ncomms3772] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 10/15/2013] [Indexed: 12/23/2022] Open
Abstract
Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.
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Affiliation(s)
- M Petrović
- Institut za fiziku, Bijenička 46, 10000 Zagreb, Croatia
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Pletikosić I, Gu GD, Valla T. Inducing a Lifshitz transition by extrinsic doping of surface bands in the topological crystalline insulator Pb1-xSnxSe. Phys Rev Lett 2014; 112:146403. [PMID: 24765995 DOI: 10.1103/physrevlett.112.146403] [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: 01/16/2014] [Indexed: 06/03/2023]
Abstract
The narrow gap semiconductor Pb1-xSnxSe was investigated for topologically protected surface states in its rocksalt structural phase for x=0.45, 0.23, 0.15, and 0. Angle-resolved photoelectron spectroscopy of intrinsically p-doped samples showed a clear indication of two Dirac cones, eccentric about the time-reversal invariant point X¯ of the surface Brillouin zone for all but the x=0 sample. Adsorption of alkalies gradually filled the surface bands with electrons, driving the x>0 topological crystalline insulator systems through Lifshitz transitions, and from a holelike to electronlike Fermi surface. The electron-doped bands in x>0 samples exhibited the full configuration of the Dirac cones, also confirming electron-hole symmetry of the surface bands.
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Affiliation(s)
- I Pletikosić
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - T Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Pletikosić I, Kralj M, Sokčević D, Brako R, Lazić P, Pervan P. Photoemission and density functional theory study of Ir(111); energy band gap mapping. J Phys Condens Matter 2010; 22:135006. [PMID: 21389509 DOI: 10.1088/0953-8984/22/13/135006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have performed combined angle-resolved photoemission spectroscopy (ARPES) experiments and density functional theory (DFT) calculations of the electronic structure of the Ir(111) surface, with the focus on the existence of energy band gaps. The investigation was motivated by the experimental results suggesting Ir(111) as an ideal support for the growth of weakly bonded graphene. Therefore, our prime interest was electronic structure around the [Formula: see text] symmetry point. In accordance with DFT calculations, ARPES has shown a wide energy band gap with the shape of a parallelogram centred around the [Formula: see text] point. Within the gap three surface states were identified; one just below the Fermi level and two spin-orbit split surface states at the bottom of the gap.
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Pletikosić I, Kralj M, Pervan P, Brako R, Coraux J, N'diaye AT, Busse C, Michely T. Dirac cones and minigaps for graphene on Ir(111). Phys Rev Lett 2009; 102:056808. [PMID: 19257540 DOI: 10.1103/physrevlett.102.056808] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Indexed: 05/27/2023]
Abstract
Epitaxial graphene on Ir(111) prepared in excellent structural quality is investigated by angle-resolved photoelectron spectroscopy. It clearly displays a Dirac cone with the Dirac point shifted only slightly above the Fermi level. The moiré resulting from the overlaid graphene and Ir(111) surface lattices imposes a superperiodic potential giving rise to Dirac cone replicas and the opening of minigaps in the band structure.
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Affiliation(s)
- I Pletikosić
- Institut za fiziku, Bijenicka 46, 10000 Zagreb, Croatia
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