Theory of “Ferrisuperconductivity” in ${U_{1-\mathit{x}}\mathrm{Th}}_{\mathit{x}}{\mathrm{Be}}_{13}$

We construct a two component Ginzburg-Landau theory with coherent pair motion and incoherent quasiparticles for the phase diagram of ${\mathrm{U}}_{1-x}{\mathrm{Th}}_x{\mathrm{Be}}_{13}$. The two staggered superconducting states live at the Brillouin zone center and the zone boundary and coexist for temperatures $T\le T_{c2\mathrm{}}$ at concentrations $x_{c1\mathrm{}}\approx 0.02\le x\le x_{c2\mathrm{}}\approx 0.04$. We predict below $T_{c2\mathrm{}}$ the appearance of a charge density wave (CDW) and Be-sublattice distortion. The distortion explains the muon spin relaxation anomaly; Th-impurity mediated scattering of ultrasound to CDW fluctuations explains the attenuation peak.