Tensor-boson condensation in superconductivity of heavy-fermion systems

Abstract

A theory of heavy-fermion superconductivity is proposed based on a tensor-boson condensation within an $\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$ Anderson-lattice model in which $f^0$, $f^1$, and $f^2$ states are allowed. The order parameter is a multiplet for $N>\mathrm{}2\mathrm{}$. In an $s$-wave model, a Kondo-like expression for the gap is obtained, and $T_c$ and $H_c$ are calculated. Estimates for Ce${\mathrm{Cu}}_2$ ${\mathrm{Si}}_2$ give $T_c$ of the correct order of magnitude.