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...
| Autores: | , , , , , , , |
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| 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 |
| Sumario: | 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 |
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