Funding
EMP is funded through the Horizon2020 programme of the European Commission.
Selected Publications
 

Zeeman-driven superconductor-insulator transition in strongly disordered MoC films: Scanning tunneling microscopy and transport studies in a transverse magnetic field

M. Žemlička, M. Kopčík, P. Szabó, T. Samuely, J. Kačmarčík, P. Neilinger, M. Grajcar, P. Samuely

The superconductor-insulator transition in a transverse magnetic field is studied in a 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 the superconducting state it is evidenced by a high upper critical magnetic field B c 2 , 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 c 2 a logarithmic anomaly in DOS is observed. This anomaly is further enhanced in an 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. A spin-dependent Altshuler-Aronov correction is also needed to explain the transport behavior above B c 2 .


Phys. Rev. B 102, 180508 (2020)

doi: 10.1103/PhysRevB.102.180508

arxiv: https://arxiv.org/abs/2011.04329