Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 18: Correlated Electrons: Quantum Impurities, Kondo Physics 2

TT 18.6: Vortrag

Dienstag, 27. März 2012, 10:45–11:00, H 3005

Non-Fermi liquid physics in two-channel Kondo models — •Andrew Mitchell — Institut für Theoretische Physik, Universität zu Köln, Germany

The two-channel Kondo (2CK) model possesses a non-Fermi liquid (NFL) quantum critical point, arising when two conduction channels compete to Kondo-screen a single spin-12 impurity. The two-impurity Kondo (2IK) model also has a NFL critical point. We establish an exact connection between the models, showing that the 2IK critical fixed point is identical to that of a 2CK model with potential scattering. Furthermore, we demonstrate that the same critical physics arises in chains of impurities, and the spin-S generalization of the 2IK model. But conductance lineshapes measurable in experiment encode the full RG flow. We study the onset of NFL physics, showing that distinctive signatures arise as a function of device asymmetry; and the ultimate recovery of standard Fermi liquid behavior resulting from symmetry-breaking perturbations.
Mitchell, Sela, Logan, arXiv:1111.6503v1 (2011)
Mitchell, Logan, Krishnamurthy, Phys. Rev. B 84, 035119 (2011)
Sela, Mitchell, Fritz, Phys. Rev. Lett. 106, 147202 (2011)