Exotic heavy-fermion superconductivity in atomically thin CeCoIn5 films
Abstract
We report an in situ scanning tunneling microscopy study of atomically thin films of CeCoIn5, a d -wave heavy-fermion superconductor. Both hybridization and superconducting gaps are observed even in monolayer CeCoIn5, providing direct evidence of superconductivity of heavy quasiparticles mediated by purely two-dimensional bosonic excitations. In these atomically thin films, Tc is suppressed to nearly half of the bulk, but is similar to CeCoIn5/YbCoIn5 superlattices containing CeCoIn5 layers with the same thickness as the thin films. Remarkably, the out-of-plane upper critical field μ0Hc 2 ⊥ at zero temperature is largely enhanced from those of bulk and superlattices. The enhanced Hc 2 ⊥ well exceeds the Pauli and bulk orbital limits, suggesting the possible emergence of unusual superconductivity with parity mixing caused by the inversion symmetry breaking.
- Publication:
-
Physical Review B
- Pub Date:
- January 2023
- DOI:
- 10.1103/PhysRevB.107.L041101
- arXiv:
- arXiv:2303.09918
- Bibcode:
- 2023PhRvB.107d1101P
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- Phys. Rev. B 107, L041101 (2023)