Josephson coupling in lanthanum-based cuprate superlattices
In most anisotropic compounds such as bismuth-based layered cuprate perovskites, the supercurrent across the blocking layer is of Josephson type, and a single crystal forms a natural stack of Josephson junctions. Here, we report on the evidence of Josephson-like transport in an artificial cuprate su...
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AIP Publishing LLC
2025-03-01
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| Series: | APL Quantum |
| Online Access: | http://dx.doi.org/10.1063/5.0251121 |
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| author | H. G. Ahmad D. Massarottti F. Tafuri G. Logvenov A. Bianconi G. Campi |
| author_facet | H. G. Ahmad D. Massarottti F. Tafuri G. Logvenov A. Bianconi G. Campi |
| author_sort | H. G. Ahmad |
| collection | DOAJ |
| description | In most anisotropic compounds such as bismuth-based layered cuprate perovskites, the supercurrent across the blocking layer is of Josephson type, and a single crystal forms a natural stack of Josephson junctions. Here, we report on the evidence of Josephson-like transport in an artificial cuprate superlattice composed of 10 LaSrCuO–LaCuO repeats, creating a superlattice of junctions, where LCO is a superconducting Mott insulator and LSCO is an overdoped metal. The superlattice has been designed with a long period of d = L + W = 5.28 nm, with L and W being the thicknesses of LCO and LSCO units, respectively, and is in the underdoped regime with an average doping level of ⟨δ⟩ = 0.11. Quantum-size effects and Rashba spin–orbit coupling are controlled by L/d = 0.75, with a quasi-2D superconducting transition temperature of 41 K and a c-axis coherence length of about 1.5 nm. Measurements at very low temperatures show evidence of Josephson phase dynamics consistent with very low Josephson coupling and a phase diffusion regime, thus explaining why Josephson coupling in LSCO superlattices has been so elusive. The tuning of LSCO superlattices in the Josephson regime enriches the phase diagram of HTS. |
| format | Article |
| id | doaj-art-8d7b68a1ee194295ac9638d2afb817f1 |
| institution | DOAJ |
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| language | English |
| publishDate | 2025-03-01 |
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| spelling | doaj-art-8d7b68a1ee194295ac9638d2afb817f12025-08-20T03:06:19ZengAIP Publishing LLCAPL Quantum2835-01032025-03-0121016113016113-710.1063/5.0251121Josephson coupling in lanthanum-based cuprate superlatticesH. G. Ahmad0D. Massarottti1F. Tafuri2G. Logvenov3A. Bianconi4G. Campi5Department of Physics “Ettore Pancini,” University Federico II, Naples 80126, ItalyDepartment of Electrical Engineering and Information Technology, University Federico II, Naples 80126, ItalyDepartment of Physics “Ettore Pancini,” University Federico II, Naples 80126, ItalyMax Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, GermanyRICMASS Rome International Centre Materials Science Superstripes, Via dei Sabelli 119A, 00185 Rome, ItalyInstitute of Crystallography, National Research Council of Italy, Via Salaria Km 29.300, Monterotondo 00015, Rome, ItalyIn most anisotropic compounds such as bismuth-based layered cuprate perovskites, the supercurrent across the blocking layer is of Josephson type, and a single crystal forms a natural stack of Josephson junctions. Here, we report on the evidence of Josephson-like transport in an artificial cuprate superlattice composed of 10 LaSrCuO–LaCuO repeats, creating a superlattice of junctions, where LCO is a superconducting Mott insulator and LSCO is an overdoped metal. The superlattice has been designed with a long period of d = L + W = 5.28 nm, with L and W being the thicknesses of LCO and LSCO units, respectively, and is in the underdoped regime with an average doping level of ⟨δ⟩ = 0.11. Quantum-size effects and Rashba spin–orbit coupling are controlled by L/d = 0.75, with a quasi-2D superconducting transition temperature of 41 K and a c-axis coherence length of about 1.5 nm. Measurements at very low temperatures show evidence of Josephson phase dynamics consistent with very low Josephson coupling and a phase diffusion regime, thus explaining why Josephson coupling in LSCO superlattices has been so elusive. The tuning of LSCO superlattices in the Josephson regime enriches the phase diagram of HTS.http://dx.doi.org/10.1063/5.0251121 |
| spellingShingle | H. G. Ahmad D. Massarottti F. Tafuri G. Logvenov A. Bianconi G. Campi Josephson coupling in lanthanum-based cuprate superlattices APL Quantum |
| title | Josephson coupling in lanthanum-based cuprate superlattices |
| title_full | Josephson coupling in lanthanum-based cuprate superlattices |
| title_fullStr | Josephson coupling in lanthanum-based cuprate superlattices |
| title_full_unstemmed | Josephson coupling in lanthanum-based cuprate superlattices |
| title_short | Josephson coupling in lanthanum-based cuprate superlattices |
| title_sort | josephson coupling in lanthanum based cuprate superlattices |
| url | http://dx.doi.org/10.1063/5.0251121 |
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