Physical Review B 85, 165118 (2012)

SCI

Preformed heavy electrons: A possible origin of characteristic energy scale in YbRh2Si2

Minh-Tien Tran, A. Benlagra, C. P´epin, and Ki-Seok Kim

The existence of multiple energy scales is regarded as a signature of the Kondo breakdown mechanism for explaining the quantum critical behavior of certain heavy-fermion compounds, like YbRh2Si2. The nature of the intermediate state between the heavy Fermi liquid and the quantum critical region, however, remains elusive. In this study, we suggest an incoherent heavy-fermion scenario, where inelastic scattering with novel soft modes of the dynamical exponent z = 3 gives rise to non-Fermi liquid physics for thermodynamics and transport despite the formation of the heavy-fermion band.We discuss a crossover from z = 3 to z = 1 for quantum phase fluctuations.