Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 50: Correlated Electrons: Quantum-Critical Phenomena - Theory
TT 50.5: Talk
Tuesday, April 1, 2014, 15:00–15:15, BEY 81
Interplay of fermion and boson induced critical Kondo destruction — •Farzaneh Zamani1,2, Pedro Ribeiro1,2,3, and Stefan Kirchner1,2 — 1MPI-PKS, Dresden, Germany — 2MPI-CPFS, Dresden, Germany — 3CFIF-IST, Universidade de Lisboa, Lisboa, Portugal
An increasing number of experiments have indicated that the traditional approach to continuous zero-temperature phase transitions in strongly correlated electrons systems is inadequate. In the context of intermetallic rare-earth compounds this approach does e.g. not account for the linear-in-temperature relaxation rates observed in a number of systems in the charge- and spin-response near criticality. A widely discussed alternative to the standard approach picture is local Kondo destruction, where Kondo screening becomes critical concomittantly with the lattice. We study the phenomenon of critical Kondo destruction in the pseudogap Bose-Fermi Kondo model where a quantum spin is coupled to a fermionic and a bosonic bath. Each of the baths by itself is capable of critically destroying Kondo screening, allowing us to study the dynamic interplay of the two. We employ a dynamic large-N limit and obtain asymptotically exact solutions at zero temperature. We also report full scaling equations at all critical points and discuss the ensuing relaxation rates. Finally, we revisit the issue of 'conformal scaling' of the imaginary-time correlation functions at criticality and relate our findings to their counterpart in the easy-axis pseudogap pseudogap Bose-Fermi Kondo model.