Field-induced quantum criticality in the heavy-fermion metal Yb2Pt2Pb*

We study non-Fermi-liquid behavior due to local criticality in the heavy-fermion metal Yb2Pt2Pb. In this material fractionalized local moments are hardly hybridized with itinerant conduction electrons and behave like quasi one-dimensional spin-1/2 chains with an excitation gap. The gap can be tuned to zero via an external magnetic field. As an advantage of the one-dimensionality, the exact form of the corresponding soft modes is known so that we can account for the non-trivial dynamics of the local moments in a clear, analytical way. The weak coupling to three-dimensional electrons induces non-Fermi-liquid behavior. We calculate the resulting electronic scattering rate and resistivity in the critical regime with perturbation theory. We find a linear scaling with temperature, which agrees with experimental data.