Mottled Electronic State Near a Quantum Critical Phase Transition(Research)

Abstract

By means of nuclear magnetic resonance (NMR) spin-lattice relaxation time measurements on a single crystal YbRh_2Si_2 sample, it is revealed that the coexisting Fermi and non-Fermi states appears near the quantum critical phase transition. Such a mottled state has remained hidden in Ce and U heavy fermion compounds, owing presumably to short lifetimes for the two states. Valence and magnetic instabilities are considered to occur at the same time around the quantum critical phase transition.