Superconductivity in heavy fermion compounds

TL;DR

This paper reviews experimental and theoretical research on heavy fermion superconductors, focusing on Ce- and U-based compounds, their quantum criticality, non-Fermi liquid behavior, and unconventional pairing mechanisms.

Contribution

It provides a comprehensive overview of recent findings and models explaining superconductivity in heavy fermion materials, highlighting the role of quantum criticality and dual electron models.

Findings

Neutron scattering and pressure studies reveal SDW/SC competition in Ce122.

Dual models with localized and itinerant electrons explain mass enhancement.

Itinerant spin fluctuation theories support unconventional pairing mechanisms.

Abstract

We review the current state of experimental and theoretical investigations of heavy fermion superconductors. We discuss most of the Ce-based compounds like Ce122, Ce115, Ce218 and Ce131 classes and U-based superconductors like UBe_13 and UPd_2Al_3. In the former the emphasis is on the connection to quantum critical phenomena and non-Fermi liquid behaviour. Recent neutron scattering and hydrostatic pressure results on SDW/SC competition in the Ce122 system are included. For the U-compounds we discuss the significance of dual models with both localised and itinerant 5f electrons for mass enhancement and superconducting pair formation. Itinerant spin fluctuation theories for unconventional superconductivity are also reviewed.