Work

Contact-induced Andreev bound states in normal-metal/superconductor planar junctions

Year: 2025

Type: article

Abstract: ABSTRACT Tunneling spectroscopy is a powerful tool for investigating the pairing mechanism of superconductors. However, the use of planar tunneling junctions to characterize Andreev bound states associated with unconventional superconductivity remains largely unexplored. Here, we report tunneling spectroscopy studies of normal-metal/superconductor planar junctions, leveraging the newly discovered LaAlO3/KTaO3(111) superconducting interface. We observe distinct spectroscopic behaviors for weak and strong tunneling barriers, controlled by the thickness of the LaAlO3: when the barrier is weak, the metallic contact couples strongly with the interface superconductor, resulting in pronounced double peaks within the superconducting gap; when the barrier is strong, the in-gap peaks diminish and a softened full superconducting gap profile emerges. These observations, supported by theoretical calculations, pinpoint the presence of contact-induced Andreev bound states in planar junctions. This not only reveals the possibility of p-wave superconductivity at the LaAlO3/KTaO3 interface but also offers a universal approach to identifying the most sought-after superconducting states.

Source: National Science Review

DOI: 10.1093/nsr/nwaf105

Authors: Beilin Wang, Linhai Guo, Guopei Ying, Wenbu Duan, Jian Li, Changgan Zeng

Institutions: University of Science and Technology of China, Westlake University

Language: English

Topic: Physics of Superconductivity and Magnetism

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,000

Funders: National Natural Science Foundation of China, National Key Research and Development Program of China, Anhui Provincial Key Research and Development Plan, Center for Advanced Study, University of Illinois at Urbana-Champaign