Portal de Periódicos da CAPES

Variational cluster approach to s -wave pairing in heavy-fermion superconductors

2015; American Physical Society; Volume: 91; Issue: 10 Linguagem: Inglês

10.1103/physrevb.91.104508

1550-235X

Keisuke Masuda, Daisuke Yamamoto,

Rare-earth and actinide compounds

We study s-wave Cooper pairing in heavy-fermion systems. We analyze the periodic Anderson model by means of the variational cluster approach (VCA) focusing on the interorbital Cooper pairing between a conduction electron ($c$ electron) and an $f$ electron, called the "$c$-$f$ pairing." It is shown that the s-wave superconductivity appears coexisting with long-range antiferromagnetic order when electrons or holes are doped into the system at half filling. The antiferromagnetic order vanishes when the doping concentration exceeds a certain critical value, leading to a pure s-wave superconducting state. Moreover, the comparative study with different reference systems used in the VCA shows that the interorbital $c$-$f$ pairing is essential for the appearance of the s-wave superconductivity.