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Tang F, Wang P, Wang Q, Gan Y, Lyu J, Mi X, He M, Zhang L, Smet JH. Ambipolar Superconductivity with Strong Pairing Interaction in Monolayer 1T'-MoTe 2. NANO LETTERS 2023; 23:7516-7523. [PMID: 37540083 PMCID: PMC10450800 DOI: 10.1021/acs.nanolett.3c02033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/14/2023] [Indexed: 08/05/2023]
Abstract
Gate tunable two-dimensional (2D) superconductors offer significant advantages in studying superconducting phase transitions. Here, we address superconductivity in exfoliated 1T'-MoTe2 monolayers with an intrinsic band gap of ∼7.3 meV using field effect doping. Despite large differences in the dispersion of the conduction and valence bands, superconductivity can be achieved easily for both electrons and holes. The onset of superconductivity occurs near 7-8 K for both charge carrier types. This temperature is much higher than that in bulk samples. Also the in-plane upper critical field is strongly enhanced and exceeds the BCS Pauli limit in both cases. Gap information is extracted using point-contact spectroscopy. The gap ratio exceeds multiple times the value expected for BCS weak-coupling. All of these observations suggest a strong enhancement of the pairing interaction.
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Affiliation(s)
- Fangdong Tang
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - Peipei Wang
- Department
of Physics and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qixing Wang
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - Yuan Gan
- Department
of Physics and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jian Lyu
- Department
of Physics and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xinrun Mi
- Low
Temperature Physics Laboratory, College of Physics & Center of
Quantum Materials and Devices, Chongqing
University, Chongqing 401331, China
| | - Mingquan He
- Low
Temperature Physics Laboratory, College of Physics & Center of
Quantum Materials and Devices, Chongqing
University, Chongqing 401331, China
| | - Liyuan Zhang
- Department
of Physics and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jurgen H. Smet
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
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Veyrat A, Labracherie V, Bashlakov DL, Caglieris F, Facio JI, Shipunov G, Charvin T, Acharya R, Naidyuk Y, Giraud R, van den Brink J, Büchner B, Hess C, Aswartham S, Dufouleur J. Berezinskii-Kosterlitz-Thouless Transition in the Type-I Weyl Semimetal PtBi 2. NANO LETTERS 2023; 23:1229-1235. [PMID: 36720048 DOI: 10.1021/acs.nanolett.2c04297] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Symmetry breaking in topological matter has become in recent years a key concept in condensed matter physics to unveil novel electronic states. In this work, we predict that broken inversion symmetry and strong spin-orbit coupling in trigonal PtBi2 lead to a type-I Weyl semimetal band structure. Transport measurements show an unusually robust low dimensional superconductivity in thin exfoliated flakes up to 126 nm in thickness (with Tc ∼ 275-400 mK), which constitutes the first report and study of unambiguous superconductivity in a type-I Weyl semimetal. Remarkably, a Berezinskii-Kosterlitz-Thouless transition with TBKT ∼ 310 mK is revealed in up to 60 nm thick flakes, which is nearly an order of magnitude thicker than the rare examples of two-dimensional superconductors exhibiting such a transition. This makes PtBi2 an ideal platform to study low dimensional and unconventional superconductivity in topological semimetals.
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Affiliation(s)
- Arthur Veyrat
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Valentin Labracherie
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Dima L Bashlakov
- B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine (NASU), 47 Nauky Avenue, 61103Kharkiv, Ukraine
| | - Federico Caglieris
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
- CNR-SPIN, Corso Perrone 24, 16152Genova, Italy
- Department of Physics, University of Genoa, Via Dodecaneso 33, 16146Genova, Italy
| | - Jorge I Facio
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
- Centro Atómico Bariloche, Instituto Balseiro and Instituto de Nanociencia y Nanotecnología CNEA-CONICET, CNEA, 8400Bariloche, Argentina
| | - Grigory Shipunov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Titouan Charvin
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Rohith Acharya
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Yurii Naidyuk
- B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine (NASU), 47 Nauky Avenue, 61103Kharkiv, Ukraine
| | - Romain Giraud
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
- Université Grenoble Alpes, CNRS, CEA, Grenoble-INP, Spintec, F-38000Grenoble, France
| | - Jeroen van den Brink
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
- Department of Physics, TU Dresden, D-01062Dresden, Germany
| | - Christian Hess
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
- Center for Transport and Devices, TU Dresden, D-01069Dresden, Germany
- Fakultät für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, D-42097Wuppertal, Germany
| | - Saicharan Aswartham
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
| | - Joseph Dufouleur
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany
- Center for Transport and Devices, TU Dresden, D-01069Dresden, Germany
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Possible Evidence for Berezinskii-Kosterlitz-Thouless Transition in Ba(Fe 0.914Co 0.086) 2As 2 Crystals. MATERIALS 2021; 14:ma14216294. [PMID: 34771819 PMCID: PMC8585216 DOI: 10.3390/ma14216294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 11/24/2022]
Abstract
In this study, we measure the in-plane transport properties of high-quality Ba(Fe0.914Co0.086)2As2 single crystals. Signatures of vortex unbinding Berezinskii–Kosterlitz–Thouless (BKT) transition are shown from both the conventional approach and the Fisher–Fisher–Huse dynamic scaling analysis, in which a characteristic Nelson–Kosterlitz jump is demonstrated. We also observe a non-Hall transverse signal exactly at the superconducting transition, which is explained in terms of guided motion of unbound vortices.
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