Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films

Nitride-based superconductors represent a family of superconducting thin film materials displaying higher quality than their corresponding bare superconductor when used in devices for applications such as cosmic radiation sensing. In recent times, niobiumbased and titanium-based nitrides were used t...

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Detalles Bibliográficos
Autores: Moreno Flores, José Antonio, García Talavera, Pablo, Torras-Coloma, Alba, Rius, Gemma, Forn-Díaz, P., Herrera Vasco, Edwin, Guillamón Gómez, Isabel, Suderow Rodríguez, Hermann Jesús
Tipo de recurso: artículo
Fecha de publicación:2026
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:dnet:biblosearchi::d74e0bb36865e2c6f453890ebc118ec2
Acceso en línea:https://hdl.handle.net/10486/756302
https://dx.doi.org/10.1007/s10909-026-03390-y
Access Level:acceso abierto
Palabra clave:Superconductivity
Thin films
Nitridized aluminum
Disordered superconductor
Scanning tunneling microscopy
Density of states
Física
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spelling Scanning tunneling spectroscopy of superconducting nitridized aluminum thin filmsMoreno Flores, José AntonioGarcía Talavera, PabloTorras-Coloma, AlbaRius, GemmaForn-Díaz, P.Herrera Vasco, EdwinGuillamón Gómez, IsabelSuderow Rodríguez, Hermann JesúsSuperconductivityThin filmsNitridized aluminumDisordered superconductorScanning tunneling microscopyDensity of statesFísicaNitride-based superconductors represent a family of superconducting thin film materials displaying higher quality than their corresponding bare superconductor when used in devices for applications such as cosmic radiation sensing. In recent times, niobiumbased and titanium-based nitrides were used to improve the quality of superconducting devices in quantum technology applications. Recently, nitridized aluminum (NitrAl) has been found to display higher critical temperatures and enhanced resilience to magnetic fields compared to those of Al, making it a new interesting candidate for superconducting quantum circuit applications. However, the microscopic properties of NitrAl remain highly unexplored. Here, we use scanning tunneling microscope (STM) to measure the superconducting density of states of a thin film sample of nitridized aluminum (NitrAl), with a room temperature resistivity between pure Al and fully insulating aluminum nitride. We show that the in-gap density of states is zero up to about ω = 250 μeV and that there is a distribution of values of the superconducting gap around 0 = 360 μeV, close to the BCS expectation = 1.76kBTc. We also find varying superconducting gap values at the nanometer scale, by approximately 10%, when probing different regions of the sample. These results suggest a gap which is larger than the one of pure Al and is spatially more homogeneous than the superconducting gap values often found in thin films. Our work demonstrates that STM is as a powerful tool to screen materials for quantum devices through the measurement of the spatial dependence of the superconducting density of statesWe acknowledge support by the Spanish Research State Agency (PID2023- 150148OB-I00, TED2021-130546BI00, PDC2021-121086-I00 and CEX2023-001316-M, PID2020- 114071RB-I00, RYC2019-028482- I, PCI2019-111838-2, PID2021-122140NB-C31, PID2021- 122140NB-C32, PCI2024- 153468, CEX2023-001397-M) and the Comunidad de Madrid through projects TEC-2024/TEC-380 “Mag4TIC” and PIPF-2023/TEC-30683. We acknowledge the “QUASURF” project [SI4/PJI/2024-00199] funded by the Comunidad de Madrid through the direct grant agreement for the promotion and development of research and technology transfer at the Universidad Autónoma de Madrid. We have benefited from collaborations through EU program Cost CA21144 (Superqumap), from SEGAINVEX at UAM in the design and construction of STM and cryogenic equipment, and from the micronanofabs infrastructure. We also acknowledge the European Commission (QuantERA SiUCs and QRADES), and program ‘Doctorat Industrial’ of the Agency for Management of University and Research Grants (2024 DI 00004). IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. This study was supported by MICIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat de CatalunyaSpringerDepartamento de Física de la Materia CondensadaFacultad de CienciasGobierno de España20262026-03-03research articlehttp://purl.org/coar/resource_type/c_2df8fbb1VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/10486/756302https://dx.doi.org/10.1007/s10909-026-03390-yreponame:Biblos-e Archivo. Repositorio Institucional de la UAMinstname:Universidad Autónoma de MadridInglésengopen accesshttp://purl.org/coar/access_right/c_abf2Attribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/info:eu-repo/semantics/openAccessoai:dnet:biblosearchi::d74e0bb36865e2c6f453890ebc118ec22026-06-23T12:46:27Z
dc.title.none.fl_str_mv Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
title Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
spellingShingle Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
Moreno Flores, José Antonio
Superconductivity
Thin films
Nitridized aluminum
Disordered superconductor
Scanning tunneling microscopy
Density of states
Física
title_short Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
title_full Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
title_fullStr Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
title_full_unstemmed Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
title_sort Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films
dc.creator.none.fl_str_mv Moreno Flores, José Antonio
García Talavera, Pablo
Torras-Coloma, Alba
Rius, Gemma
Forn-Díaz, P.
Herrera Vasco, Edwin
Guillamón Gómez, Isabel
Suderow Rodríguez, Hermann Jesús
author Moreno Flores, José Antonio
author_facet Moreno Flores, José Antonio
García Talavera, Pablo
Torras-Coloma, Alba
Rius, Gemma
Forn-Díaz, P.
Herrera Vasco, Edwin
Guillamón Gómez, Isabel
Suderow Rodríguez, Hermann Jesús
author_role author
author2 García Talavera, Pablo
Torras-Coloma, Alba
Rius, Gemma
Forn-Díaz, P.
Herrera Vasco, Edwin
Guillamón Gómez, Isabel
Suderow Rodríguez, Hermann Jesús
author2_role author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Departamento de Física de la Materia Condensada
Facultad de Ciencias
Gobierno de España
dc.subject.none.fl_str_mv Superconductivity
Thin films
Nitridized aluminum
Disordered superconductor
Scanning tunneling microscopy
Density of states
Física
topic Superconductivity
Thin films
Nitridized aluminum
Disordered superconductor
Scanning tunneling microscopy
Density of states
Física
description Nitride-based superconductors represent a family of superconducting thin film materials displaying higher quality than their corresponding bare superconductor when used in devices for applications such as cosmic radiation sensing. In recent times, niobiumbased and titanium-based nitrides were used to improve the quality of superconducting devices in quantum technology applications. Recently, nitridized aluminum (NitrAl) has been found to display higher critical temperatures and enhanced resilience to magnetic fields compared to those of Al, making it a new interesting candidate for superconducting quantum circuit applications. However, the microscopic properties of NitrAl remain highly unexplored. Here, we use scanning tunneling microscope (STM) to measure the superconducting density of states of a thin film sample of nitridized aluminum (NitrAl), with a room temperature resistivity between pure Al and fully insulating aluminum nitride. We show that the in-gap density of states is zero up to about ω = 250 μeV and that there is a distribution of values of the superconducting gap around 0 = 360 μeV, close to the BCS expectation = 1.76kBTc. We also find varying superconducting gap values at the nanometer scale, by approximately 10%, when probing different regions of the sample. These results suggest a gap which is larger than the one of pure Al and is spatially more homogeneous than the superconducting gap values often found in thin films. Our work demonstrates that STM is as a powerful tool to screen materials for quantum devices through the measurement of the spatial dependence of the superconducting density of states
publishDate 2026
dc.date.none.fl_str_mv 2026
2026-03-03
dc.type.none.fl_str_mv research article
http://purl.org/coar/resource_type/c_2df8fbb1
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/10486/756302
https://dx.doi.org/10.1007/s10909-026-03390-y
url https://hdl.handle.net/10486/756302
https://dx.doi.org/10.1007/s10909-026-03390-y
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Springer
publisher.none.fl_str_mv Springer
dc.source.none.fl_str_mv reponame:Biblos-e Archivo. Repositorio Institucional de la UAM
instname:Universidad Autónoma de Madrid
instname_str Universidad Autónoma de Madrid
reponame_str Biblos-e Archivo. Repositorio Institucional de la UAM
collection Biblos-e Archivo. Repositorio Institucional de la UAM
repository.name.fl_str_mv
repository.mail.fl_str_mv
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