Zeeman driven superconductor insulator transition in strongly disordered MoC film. STM and transport studies in transverse magnetic field

Superconductor insulator transition in transverse magnetic field is studied in the highly disordered MoC film with the product of the Fermi momentum and the mean free path \(k_F*l\) close to unity. Surprisingly, the Zeeman paramagnetic effects dominate over orbital coupling on both sides of the tran...

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Bibliographic Details
Published in:arXiv.org 2021-09
Main Authors: Žemlička, M, Kopčík, M, Szabó, P, Samuely, T, Kačmarčík, J, Neilinger, P, Grajcar, M, Samuely, P
Format: Article
Language:English
Subjects:
Density of states
Elementary excitations
Magnetic fields
Magnetism
Splitting
Temperature dependence
Transport phenomena
Zeeman effect
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Summary:Superconductor insulator transition in transverse magnetic field is studied in the highly disordered MoC film with the product of the Fermi momentum and the mean free path \(k_F*l\) close to unity. Surprisingly, the Zeeman paramagnetic effects dominate over orbital coupling on both sides of the transition. In superconducting state it is evidenced by a high upper critical magnetic field \(B_{c2}\), by its square root dependence on temperature, as well as by the Zeeman splitting of the quasiparticle density of states (DOS) measured by scanning tunneling microscopy. At \(B_{c2}\) a logarithmic anomaly in DOS is observed. This anomaly is further enhanced in increasing magnetic field, which is explained by the Zeeman splitting of the Altshuler-Aronov DOS driving the system into a more insulating or resistive state. Spin dependent Altshuler-Aronov correction is also needed to explain the transport behavior above \(B_{c2}\).
ISSN:2331-8422
DOI:10.48550/arxiv.2011.04329