SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 4: f-Electron Systems and Heavy Fermions I

TT 4.11: Talk

Monday, March 27, 2023, 12:15–12:30, HSZ 201

Superconductivity beyond the Pauli limit in high-pressure CeSb₂ — •Oliver Squire, Stephen Hodgson, Jiasheng Chen, Vitaly Fedoseev, Christian de Podesta, Theodore Weinberger, Patricia Alireza, and Malte Grosche — Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK

The Kondo lattice system CeSb₂ has been recently found to undergo a structural transition under applied pressure. Here, we focus on the low-temperature properties in the new high-pressure structure which hosts an ultra-heavy fermion electronic state and antiferromagnetic order.

We have accessed the high-pressure structure of CeSb₂ using both piston-cylinder and anvil pressure cells at mK temperatures, and suppressed the magnetic order to a quantum critical point. In the vicinity of the quantum critical point, we have discovered a superconducting dome with T_c = 250 mK. The upper critical field exceeds the conventional Pauli limit by almost an order of magnitude and displays an unusual S-shaped temperature dependence. We will discuss the relationship between the upper critical field, the locally non-centrosymmetric crystal structure and the strong electronic mass enhancement in CeSb₂.