Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films
Abstract Despite constituting a smaller fraction of the qubit's electromagnetic mode, surfaces and interfaces can exert significant influence as sources of high‐loss tangents, which brings forward the need to reveal properties of these extended defects and identify routes to their control. Here...
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| Format: | Article |
| Language: | English |
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Wiley
2025-05-01
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| Series: | Advanced Science |
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| Online Access: | https://doi.org/10.1002/advs.202413058 |
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| author | Aswin k. Anbalagan Rebecca Cummings Chenyu Zhou Junsik Mun Vesna Stanic Jean Jordan‐Sweet Juntao Yao Kim Kisslinger Conan Weiland Dmytro Nykypanchuk Steven L. Hulbert Qiang Li Yimei Zhu Mingzhao Liu Peter V. Sushko Andrew L. Walter Andi M. Barbour |
| author_facet | Aswin k. Anbalagan Rebecca Cummings Chenyu Zhou Junsik Mun Vesna Stanic Jean Jordan‐Sweet Juntao Yao Kim Kisslinger Conan Weiland Dmytro Nykypanchuk Steven L. Hulbert Qiang Li Yimei Zhu Mingzhao Liu Peter V. Sushko Andrew L. Walter Andi M. Barbour |
| author_sort | Aswin k. Anbalagan |
| collection | DOAJ |
| description | Abstract Despite constituting a smaller fraction of the qubit's electromagnetic mode, surfaces and interfaces can exert significant influence as sources of high‐loss tangents, which brings forward the need to reveal properties of these extended defects and identify routes to their control. Here, we examine the structure and composition of the metal‐substrate interfacial layer that exists in Ta/sapphire‐based superconducting films. Synchrotron‐based X‐ray reflectivity measurements of Ta films, commonly used in these qubits, reveal an unexplored interface layer at the metal‐substrate interface. Scanning transmission electron microscopy and core‐level electron energy loss spectroscopy identified an intermixing layer (≈0.65 ± 0.05 nm) at the metal‐substrate interface containing Al, O, and Ta atoms. Density functional theory modeling reveals that the structure and properties of the Ta/sapphire heterojunctions are determined by the oxygen content on the sapphire surface prior to Ta deposition for two atomic terminations of sapphire. Using a multimodal approach, we gained deeper insights into the interface layer between the metal and substrate, which suggests that the orientation of deposited Ta films depend on the surface termination of sapphire. The observed elemental intermixing at the metal‐substrate interface influences the thermodynamic stability and electronic behavior of the film, which may also affect qubit performance. |
| format | Article |
| id | doaj-art-1ce16343731b47aa90c80d4b34c1e1ca |
| institution | OA Journals |
| issn | 2198-3844 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advanced Science |
| spelling | doaj-art-1ce16343731b47aa90c80d4b34c1e1ca2025-08-20T02:15:06ZengWileyAdvanced Science2198-38442025-05-011217n/an/a10.1002/advs.202413058Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting FilmsAswin k. Anbalagan0Rebecca Cummings1Chenyu Zhou2Junsik Mun3Vesna Stanic4Jean Jordan‐Sweet5Juntao Yao6Kim Kisslinger7Conan Weiland8Dmytro Nykypanchuk9Steven L. Hulbert10Qiang Li11Yimei Zhu12Mingzhao Liu13Peter V. Sushko14Andrew L. Walter15Andi M. Barbour16National Synchrotron Light Source II Brookhaven National Laboratory Upton New York 11973 USAThe Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USACenter for Functional Nanomaterials Brookhaven National Laboratory Upton New York 11973 USAThe Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USAIBM T. J. Watson Research Center 1101 Kitchawan Road Yorktown Heights New York 10598 USAIBM T. J. Watson Research Center 1101 Kitchawan Road Yorktown Heights New York 10598 USAThe Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USACenter for Functional Nanomaterials Brookhaven National Laboratory Upton New York 11973 USAMaterial Measurement Laboratory National Institute of Standard and Technology Gaithersburg Maryland 20899 USACenter for Functional Nanomaterials Brookhaven National Laboratory Upton New York 11973 USANational Synchrotron Light Source II Brookhaven National Laboratory Upton New York 11973 USAThe Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USAThe Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USACenter for Functional Nanomaterials Brookhaven National Laboratory Upton New York 11973 USAPhysical and Computational Sciences Directorate Pacific Northwest National Laboratory Richland Washington 99354 USANational Synchrotron Light Source II Brookhaven National Laboratory Upton New York 11973 USANational Synchrotron Light Source II Brookhaven National Laboratory Upton New York 11973 USAAbstract Despite constituting a smaller fraction of the qubit's electromagnetic mode, surfaces and interfaces can exert significant influence as sources of high‐loss tangents, which brings forward the need to reveal properties of these extended defects and identify routes to their control. Here, we examine the structure and composition of the metal‐substrate interfacial layer that exists in Ta/sapphire‐based superconducting films. Synchrotron‐based X‐ray reflectivity measurements of Ta films, commonly used in these qubits, reveal an unexplored interface layer at the metal‐substrate interface. Scanning transmission electron microscopy and core‐level electron energy loss spectroscopy identified an intermixing layer (≈0.65 ± 0.05 nm) at the metal‐substrate interface containing Al, O, and Ta atoms. Density functional theory modeling reveals that the structure and properties of the Ta/sapphire heterojunctions are determined by the oxygen content on the sapphire surface prior to Ta deposition for two atomic terminations of sapphire. Using a multimodal approach, we gained deeper insights into the interface layer between the metal and substrate, which suggests that the orientation of deposited Ta films depend on the surface termination of sapphire. The observed elemental intermixing at the metal‐substrate interface influences the thermodynamic stability and electronic behavior of the film, which may also affect qubit performance.https://doi.org/10.1002/advs.202413058density functional theory modelingHAADF‐STEMsuperconducting filmssynchrotron X‐ray reflectivitytantalum |
| spellingShingle | Aswin k. Anbalagan Rebecca Cummings Chenyu Zhou Junsik Mun Vesna Stanic Jean Jordan‐Sweet Juntao Yao Kim Kisslinger Conan Weiland Dmytro Nykypanchuk Steven L. Hulbert Qiang Li Yimei Zhu Mingzhao Liu Peter V. Sushko Andrew L. Walter Andi M. Barbour Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films Advanced Science density functional theory modeling HAADF‐STEM superconducting films synchrotron X‐ray reflectivity tantalum |
| title | Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films |
| title_full | Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films |
| title_fullStr | Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films |
| title_full_unstemmed | Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films |
| title_short | Revealing the Origin and Nature of the Buried Metal‐Substrate Interface Layer in Ta/Sapphire Superconducting Films |
| title_sort | revealing the origin and nature of the buried metal substrate interface layer in ta sapphire superconducting films |
| topic | density functional theory modeling HAADF‐STEM superconducting films synchrotron X‐ray reflectivity tantalum |
| url | https://doi.org/10.1002/advs.202413058 |
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