41 research outputs found
A Superconducting Instability in the Infinite-U Anderson Lattice in the Presence of Crystal Electric Fields
We report evidence of a superconducting instability (of symmetry) in
the infinite-U Anderson lattice in the presence of crystal fields of cubic
symmetry. We assume a lattice of sites, each with a total angular momentum
of that is split by crystal fields into a low-lying doublet of
symmetry and an excited quartet of symmetry. Slave Bosons
on the sites create and destroy configurations and Lagrange
multipliers at each site enforce the occupancy constraint due to the
infinite Coulomb repulsion. Quasiparticle interactions are due to exchange of
density fluctuations, which are represented by fluctuations in the slave
Bosons and Lagrange multipliers. We use the so-called analytic tetrahedron
method to calculate the dressed (to order 1/N) Boson Green functions. In weak
couping, the exchange of the dressed Bosons gives rise to a superconducting
instability of , , symmetry. The , ``s-wave'',
channel has strongly repulsive interactions and hence no pairing instability.
The channel exhibits weakly repulsive interactions. Average
quasiparticle interactions in the , , , channel
fluctuate strongly as a function of the number of tetrahedra used to calculate
the Bosonic Green functions,Comment: 66 pages+ 17 postscript figures, LATE