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TT: Fachverband Tiefe Temperaturen

TT 45: Correlated Electrons: Poster Session

TT 45.35: Poster

Donnerstag, 29. März 2012, 15:00–19:00, Poster B

Quantum Criticality in the pseudogap Kondo model: a dynamical large-N study — •Farzaneh Zamani, Pedro Ribeiro, and Stefan Kirchner — Max Planck Institute for the Physics of Complex Systems

In the pseudogap Kondo model, a continuous zero-temperature phase transition separates a Kondo-screened phase from a Kondo-destroyed local moment phase. This model is a prototype system to study critical Kondo destruction which has been observed in various intermetallic rare earth compounds. It is also the effective low-energy model to describe point-defects in graphene and non-magnetic impurities in d-wave superconductors and can be realized in certain quantum dot systems. We address the critical properties of the SU(N)XSU(M) pseudogap Kondo model in a dynamical large-N limit [1,2]. Applying the scaling ansatz of [1,3], we obtain the leading and critical exponents in the quantum coherent regime (ℏ ω≪ k_B T). Solving the large-N equations, we obtain the full scaling functions in both the quantum coherent and relaxational regime (k_B T ≪ ℏ ω). The local critical correlators have the form of a local conformally invariant fixed point although the underlying model lacks conformal symmetry in the bulk.
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