Heavy electron quantum criticality: Perspectives and challenges for single-electron spectroscopy

Our new preprint reviews existing scanning tunneling and angle-resolved photoemission spectrocopy studies in the context of Kondo-destroying quantum criticality in heavy-electron compounds. A discussion of current challenges, prospects and future research for single-electron spectroscopy near quantum criticality is provided.

Illustrations of basic concepts of Kondo-destruction quantum criticality: Local quantum criticality with Kondo destruction, under the variation of the control parameter δ. Here, T₀ is a high-energy scale that describes the initial onset of dynamical Kondo correlations and that smoothly evolves across the QCP. This high-energy scale is reflected in the onset of hybridization-gap formation. The low-energy physics is described in terms of T_N and T_FL which are respectively the temperatures for the Néel transition and the crossover into the paramagnetic Fermi-liquid state.
This phase diagram also involves the Kondo-destruction energy scale E^*_loc, which characterizes the Kondo destruction. The E^*_loc-line divides the phase diagram in terms of the flow of the system towards either the Kondo-screened or the Kondo-destruction ground state.