On the origin of heavy quasiparticles in LiV2O4

An explanation is provided for the heavy quasiparticle excitations in LiV2O 4. It differs considerably from that of other known heavy-fermion systems. Main ingredients of our theory are the cubic spinel structure of the materi al and strong short-range correlations of the d electrons. The large gamma coefficient is shown to result from excitations of Heisenberg spin 1/2 ring s and chains. The required coupling constant is calculated from LDA+U calcu lations and is found to be of the right size. Also the calculated Sommerfel d-Wilson ratio is reasonably close to the observed one.