Quantum spin liquid in an RKKY-coupled two-impurity Kondo system

We consider a 2-impurity Kondo system with spin-exchange coupling within the conduction band. Our numerical renormalization group calculations show that for strong intraband spin correlations competition of these screening stabilizes metallic spin-liquid phase localized spins without geometric frustration. For weak liquid and singlet are separated by two quantum transitions an intermediate RKKY spin-dimer phase, while beyond critical they connected crossover. The results suggest how may be realized in heavy-fermion systems near spin-density wave instability.