Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 53: Quantum Impurities and Kondo Physics

TT 53.5: Vortrag

Mittwoch, 14. März 2018, 10:30–10:45, HFT-FT 131

Restoring the Varma-Jones quantum critical point in absence of local particle-hole symmetry — •Fabian Eickhoff¹, Benedikt Lechtenberg², and Frithjof Anders¹ — ¹Technische Universität Dortmund, Lehrstuhl für Theoretische Physik II, 44227 Dortmund — ²Department of Physics, Kyoto University, Kyoto 606-8502, Japan

The quantum critical point (QCP) in two impurity model established by Varma and Jones marks the transition between an RKKY driven impurity singlet and a extended Kondo singlet and is generically destroyed by particle-hole symmetry breaking. We derive an effective low energy description for the two-impurity Anderson model and extract the marginal relevant operator that drives the system away from the QCP. By adding an additional electron tunneling term with an analytically calculated strength, we prove the restoration of the Varma- Jones QCP using Wilson's numerical renormalization group approach. We show that the antiferromagnetic contribution to the RKKY interaction is given by an analytic function of this hopping amplitude. We analyse the strength and directionality of the RKKY interaction in different spatial dimensions.