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Wang H, Zhu Y, Bai Z, Wang Z, Hu S, Xie HY, Hu X, Cui J, Huang M, Chen J, Ding Y, Zhao L, Li X, Zhang Q, Gu L, Zhou XJ, Zhu J, Zhang D, Xue QK. Prominent Josephson tunneling between twisted single copper oxide planes of Bi 2Sr 2-xLa xCuO 6+y. Nat Commun 2023; 14:5201. [PMID: 37626041 PMCID: PMC10457331 DOI: 10.1038/s41467-023-40525-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
Josephson tunneling in twisted cuprate junctions provides a litmus test for the pairing symmetry, which is fundamental for understanding the microscopic mechanism of high temperature superconductivity. This issue is rekindled by experimental advances in van der Waals stacking and the proposal of an emergent d+id-wave. So far, all experiments have been carried out on Bi2Sr2CaCu2O8+x (Bi-2212) with double CuO2 planes but show controversial results. Here, we investigate junctions made of Bi2Sr2-xLaxCuO6+y (Bi-2201) with single CuO2 planes. Our on-site cold stacking technique ensures uncompromised crystalline quality and stoichiometry at the interface. Junctions with carefully calibrated twist angles around 45° show strong Josephson tunneling and conventional temperature dependence. Furthermore, we observe standard Fraunhofer diffraction patterns and integer Fiske steps in a junction with a twist angle of 45.0±0.2°. Together, these results pose strong constraints on the d or d+id-wave pairing and suggest an indispensable isotropic pairing component.
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Affiliation(s)
- Heng Wang
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Yuying Zhu
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
| | - Zhonghua Bai
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Zechao Wang
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
- Ji Hua Laboratory, Foshan, Guangdong, 528200, China
| | - Shuxu Hu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Hong-Yi Xie
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Xiaopeng Hu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Jian Cui
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Miaoling Huang
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Jianhao Chen
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100091, China
| | - Ying Ding
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Lin Zhao
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xinyan Li
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Qinghua Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Lin Gu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - X J Zhou
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jing Zhu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
- Ji Hua Laboratory, Foshan, Guangdong, 528200, China
| | - Ding Zhang
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan.
| | - Qi-Kun Xue
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Southern University of Science and Technology, Shenzhen, 518055, China.
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Tian Y, Yu HF, Deng H, Xue GM, Liu DT, Ren YF, Chen GH, Zheng DN, Jing XN, Lu L, Zhao SP, Han S. A cryogen-free dilution refrigerator based Josephson qubit measurement system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:033907. [PMID: 22462938 DOI: 10.1063/1.3698001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We develop a small-signal measurement system on cryogen-free dilution refrigerator which is suitable for superconducting qubit studies. Cryogen-free refrigerators have several advantages such as less manpower for system operation and large sample space for experiment, but concern remains about whether the noise introduced by the coldhead can be made sufficiently low. In this work, we demonstrate some effective approaches of acoustic isolation to reduce the noise impact. The electronic circuit that includes the current, voltage, and microwave lines for qubit coherent state measurement is described. For the current and voltage lines designed to have a low pass of dc-100 kHz, we show that the measurements of Josephson junction's switching current distribution with a width down to 1 nA, and quantum coherent Rabi oscillation and Ramsey interference of the superconducting qubit can be successfully performed.
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Affiliation(s)
- Ye Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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Energy gaps in Bi(2)Sr(2)CaCu(2)O(8+δ) cuprate superconductors. Sci Rep 2012; 2:248. [PMID: 22355760 PMCID: PMC3272663 DOI: 10.1038/srep00248] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 01/20/2012] [Indexed: 11/09/2022] Open
Abstract
The relationship between the cuprate pseudogap (Δ(p)) and superconducting gap (Δ(s)) remains an unsolved mystery. Here, we present a temperature- and doping-dependent tunneling study of submicron Bi(2)Sr(2)CaCu(2)O(8+δ) intrinsic Josephson junctions, which provides a clear evidence that Δ(s) closes at a temperature T(c) (0) well above the superconducting transition temperature T(c) but far below the pseudogap opening temperature T*. We show that the superconducting pairing first occurs predominantly on a limited Fermi surface near the node below T(c) (0), accompanied by a Fermi arc due to the lifetime effects of quasiparticles and Cooper pairs. The arc length has a linear temperature dependence, and as temperature decreases below T(c) it reduces to zero while pairing spreads to the antinodal region of the pseudogap leading to a d-wave superconducting gap on the entire Fermi surface at lower temperatures.
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Yu HF, Zhu XB, Peng ZH, Tian Y, Cui DJ, Chen GH, Zheng DN, Jing XN, Lu L, Zhao SP, Han S. Quantum phase diffusion in a small underdamped Josephson junction. PHYSICAL REVIEW LETTERS 2011; 107:067004. [PMID: 21902362 DOI: 10.1103/physrevlett.107.067004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Indexed: 05/27/2023]
Abstract
Quantum phase diffusion in a small underdamped Nb/AlO(x)/Nb junction (∼0.4 μm(2)) is demonstrated in a wide temperature range of 25-140 mK where macroscopic quantum tunneling (MQT) is the dominant escape mechanism. We propose a two-step transition model to describe the switching process in which the escape rate out of the potential well and the transition rate from phase diffusion to the running state are considered. The transition rate extracted from the experimental switching current distribution follows the predicted Arrhenius law in the thermal regime but is greatly enhanced when MQT becomes dominant.
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Affiliation(s)
- H F Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, China
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