Topological superconductivity in EuS/Au/superconductor heterostructures
In a recent work [S. Manna, P. Wei, Y. Xie, K. T. Law, P. A. Lee, and J. S. Moodera, Proc. Natl. Acad. Sci. 117, 8775 (2020)10.1073/pnas.1919753117], signatures of a pair of Majorana bound states (MBSs) were found in an experimental platform formed by EuS islands deposited on top of a gold surface w...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2021-10-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.3.043086 |
| _version_ | 1797210847678824448 |
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| author | Ying-Ming Xie K. T. Law Patrick A. Lee |
| author_facet | Ying-Ming Xie K. T. Law Patrick A. Lee |
| author_sort | Ying-Ming Xie |
| collection | DOAJ |
| description | In a recent work [S. Manna, P. Wei, Y. Xie, K. T. Law, P. A. Lee, and J. S. Moodera, Proc. Natl. Acad. Sci. 117, 8775 (2020)10.1073/pnas.1919753117], signatures of a pair of Majorana bound states (MBSs) were found in an experimental platform formed by EuS islands deposited on top of a gold surface which was made superconducting through proximity coupling to a superconductor. In this paper, we provide a theoretical understanding for how MBSs can be formed in EuS/Au/superconductor heterostructures. We focus on the strip geometry where a narrow ferromagnetic strip is deposited on a planar structure. We first explicitly map out the topological phase diagram of the EuS/Au/superconductor heterostructure using the lattice Green's function method. Importantly, we find that the chemical potential step between the region with and without EuS covering is a crucial ingredient for the creation of MBS of this setup. Next, we focus on the Bogoliugov quasiparticles that are bound to the region under the EuS by Andreev reflections from the surrounding superconductors. Moreover, we obtain the topological regimes analytically using the scattering matrix method. Notably, we confirm that the normal reflections induced by the chemical potential step are essential for creating finite topological regimes. Furthermore, the area of the topological regimes shows periodic oscillation as a function of chemical potential as well as the sample width. We conclude by showing that the feromagnetic strip geometry holds a number of advantages over other quasi-one-dimensional schemes that have been proposed. |
| first_indexed | 2024-04-24T10:17:06Z |
| format | Article |
| id | doaj.art-3cd471fb69074774a25b36a7a41dfd33 |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:17:06Z |
| publishDate | 2021-10-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-3cd471fb69074774a25b36a7a41dfd332024-04-12T17:15:20ZengAmerican Physical SocietyPhysical Review Research2643-15642021-10-013404308610.1103/PhysRevResearch.3.043086Topological superconductivity in EuS/Au/superconductor heterostructuresYing-Ming XieK. T. LawPatrick A. LeeIn a recent work [S. Manna, P. Wei, Y. Xie, K. T. Law, P. A. Lee, and J. S. Moodera, Proc. Natl. Acad. Sci. 117, 8775 (2020)10.1073/pnas.1919753117], signatures of a pair of Majorana bound states (MBSs) were found in an experimental platform formed by EuS islands deposited on top of a gold surface which was made superconducting through proximity coupling to a superconductor. In this paper, we provide a theoretical understanding for how MBSs can be formed in EuS/Au/superconductor heterostructures. We focus on the strip geometry where a narrow ferromagnetic strip is deposited on a planar structure. We first explicitly map out the topological phase diagram of the EuS/Au/superconductor heterostructure using the lattice Green's function method. Importantly, we find that the chemical potential step between the region with and without EuS covering is a crucial ingredient for the creation of MBS of this setup. Next, we focus on the Bogoliugov quasiparticles that are bound to the region under the EuS by Andreev reflections from the surrounding superconductors. Moreover, we obtain the topological regimes analytically using the scattering matrix method. Notably, we confirm that the normal reflections induced by the chemical potential step are essential for creating finite topological regimes. Furthermore, the area of the topological regimes shows periodic oscillation as a function of chemical potential as well as the sample width. We conclude by showing that the feromagnetic strip geometry holds a number of advantages over other quasi-one-dimensional schemes that have been proposed.http://doi.org/10.1103/PhysRevResearch.3.043086 |
| spellingShingle | Ying-Ming Xie K. T. Law Patrick A. Lee Topological superconductivity in EuS/Au/superconductor heterostructures Physical Review Research |
| title | Topological superconductivity in EuS/Au/superconductor heterostructures |
| title_full | Topological superconductivity in EuS/Au/superconductor heterostructures |
| title_fullStr | Topological superconductivity in EuS/Au/superconductor heterostructures |
| title_full_unstemmed | Topological superconductivity in EuS/Au/superconductor heterostructures |
| title_short | Topological superconductivity in EuS/Au/superconductor heterostructures |
| title_sort | topological superconductivity in eus au superconductor heterostructures |
| url | http://doi.org/10.1103/PhysRevResearch.3.043086 |
| work_keys_str_mv | AT yingmingxie topologicalsuperconductivityineusausuperconductorheterostructures AT ktlaw topologicalsuperconductivityineusausuperconductorheterostructures AT patrickalee topologicalsuperconductivityineusausuperconductorheterostructures |