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Mesaros A, Gu GD, Massee F. Topologically trivial gap-filling in superconducting Fe(Se,Te) by one-dimensional defects. Nat Commun 2024; 15:3774. [PMID: 38710680 DOI: 10.1038/s41467-024-48047-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/15/2024] [Indexed: 05/08/2024] Open
Abstract
Structural distortions and imperfections are a crucial aspect of materials science, on the macroscopic scale providing strength, but also enhancing corrosion and reducing electrical and thermal conductivity. At the nanometre scale, multi-atom imperfections, such as atomic chains and crystalline domain walls have conversely been proposed as a route to topological superconductivity, whose most prominent characteristic is the emergence of Majorana Fermions that can be used for error-free quantum computing. Here, we shed more light on the nature of purported domain walls in Fe(Se,Te) that may host 1D dispersing Majorana modes. We show that the displacement shift of the atomic lattice at these line-defects results from sub-surface impurities that warp the topmost layer(s). Using the electric field between the tip and sample, we manage to reposition the sub-surface impurities, directly visualizing the displacement shift and the underlying defect-free lattice. These results, combined with observations of a completely different type of 1D defect where superconductivity remains fully gapped, highlight the topologically trivial nature of 1D defects in Fe(Se,Te).
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Affiliation(s)
- A Mesaros
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - F Massee
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France.
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Zhang Y, Mesaros A, Fujita K, Edkins SD, Hamidian MH, Ch'ng K, Eisaki H, Uchida S, Davis JCS, Khatami E, Kim EA. Machine learning in electronic-quantum-matter imaging experiments. Nature 2019; 570:484-490. [PMID: 31217587 DOI: 10.1038/s41586-019-1319-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 04/08/2019] [Indexed: 11/09/2022]
Abstract
For centuries, the scientific discovery process has been based on systematic human observation and analysis of natural phenomena1. Today, however, automated instrumentation and large-scale data acquisition are generating datasets of such large volume and complexity as to defy conventional scientific methodology. Radically different scientific approaches are needed, and machine learning (ML) shows great promise for research fields such as materials science2-5. Given the success of ML in the analysis of synthetic data representing electronic quantum matter (EQM)6-16, the next challenge is to apply this approach to experimental data-for example, to the arrays of complex electronic-structure images17 obtained from atomic-scale visualization of EQM. Here we report the development and training of a suite of artificial neural networks (ANNs) designed to recognize different types of order hidden in such EQM image arrays. These ANNs are used to analyse an archive of experimentally derived EQM image arrays from carrier-doped copper oxide Mott insulators. In these noisy and complex data, the ANNs discover the existence of a lattice-commensurate, four-unit-cell periodic, translational-symmetry-breaking EQM state. Further, the ANNs determine that this state is unidirectional, revealing a coincident nematic EQM state. Strong-coupling theories of electronic liquid crystals18,19 are consistent with these observations.
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Affiliation(s)
- Yi Zhang
- Department of Physics, Cornell University, Ithaca, NY, USA
| | - A Mesaros
- Department of Physics, Cornell University, Ithaca, NY, USA.,Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, Orsay, France
| | - K Fujita
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - S D Edkins
- Department of Physics, Cornell University, Ithaca, NY, USA.,Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - M H Hamidian
- Department of Physics, Cornell University, Ithaca, NY, USA.,Department of Physics, Harvard University, Cambridge, MA, USA
| | - K Ch'ng
- Department of Physics and Astronomy, San Jose State University, San Jose, CA, USA
| | - H Eisaki
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - S Uchida
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.,Department of Physics, University of Tokyo, Tokyo, Japan
| | - J C Séamus Davis
- Department of Physics, Cornell University, Ithaca, NY, USA.,Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA.,Department of Physics, University College Cork, Cork, Ireland.,Clarendon Laboratory, University of Oxford, Oxford, UK
| | - Ehsan Khatami
- Department of Physics and Astronomy, San Jose State University, San Jose, CA, USA
| | - Eun-Ah Kim
- Department of Physics, Cornell University, Ithaca, NY, USA.
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Mesaros A, Fujita K, Eisaki H, Uchida S, Davis JC, Sachdev S, Zaanen J, Lawler MJ, Kim EA. Topological Defects Coupling Smectic Modulations to Intra–Unit-Cell Nematicity in Cuprates. Science 2011; 333:426-30. [DOI: 10.1126/science.1201082] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- A. Mesaros
- Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, 2300 Leiden, Netherlands
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - K. Fujita
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - H. Eisaki
- Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan
| | - S. Uchida
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - J. C. Davis
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, UK
| | - S. Sachdev
- Department of Physics, Harvard University, Boston, MA 02138, USA
| | - J. Zaanen
- Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, 2300 Leiden, Netherlands
| | - M. J. Lawler
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902–6000, USA
| | - Eun-Ah Kim
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
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