Gap suppression at a Lifshitz transition in a multi-condensate superconductor
In multi-orbital materials, superconductivity can exhibit several coupled conden- sates. In this context, quantum con nement in two-dimensional superconducting oxide interfaces o ers new degrees of freedom to engineer the band structure and selectively control 3d-orbitals occupancy by electrostatic...
| Authors: | , , , , , , , , , , , , |
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| Format: | article |
| Status: | Versión aceptada para publicación |
| Publication Date: | 2019 |
| Country: | España |
| Institution: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repository: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/202855 |
| Online Access: | http://hdl.handle.net/10261/202855 |
| Access Level: | Open access |
| Keyword: | Electronic properties and materials Superconducting properties and materials Surfaces, interfaces and thin films |
| Summary: | In multi-orbital materials, superconductivity can exhibit several coupled conden- sates. In this context, quantum con nement in two-dimensional superconducting oxide interfaces o ers new degrees of freedom to engineer the band structure and selectively control 3d-orbitals occupancy by electrostatic doping. Here, we use resonant microwave transport to extract the super uid sti ness of the (110)-oriented LaAlO3/SrTiO3 in- terface in the entire phase diagram. We evidence a transition from single-condensate to two-condensate superconductivity driven by continuous and reversible electrostatic doping, which we relate to the Lifshitz transition between 3d-bands based on numerical simulations of the quantum well. We nd that the superconducting gap is suppressed while the second band is populated, challenging the Bardeen-Cooper-Schrie er theory. We ascribe this behavior to the existence of superconducting order parameters with opposite signs in the two condensates, due to a repulsive coupling. Our ndings o er an innovative perspective on the possibility to tune and control multiple-orbitals physics in superconducting interfaces. |
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