Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2003-10-10
Phys. Rev. B 69, 214413 (2004)
Physics
Condensed Matter
Strongly Correlated Electrons
24 pages, 12 figs; (v2) minor changes, flow equation section extended
Scientific paper
10.1103/PhysRevB.69.214413
We investigate a model of two Kondo impurities coupled via an Ising interaction. Exploiting the mapping to a generalized single-impurity Anderson model, we establish that the model has a singlet and a (pseudospin) doublet phase separated by a Kosterlitz-Thouless quantum phase transition. Based on a strong-coupling analysis and renormalization group arguments, we show that at this transition the conductance G through the system either displays a zero-bias anomaly, G ~ |V|^{-2(\sqrt{2}-1)}, or takes a universal value, G = e^2/(\pi\hbar) cos^2[\pi/(2\sqrt{2})], depending on the experimental setup. Close to the Toulouse point of the individual Kondo impurities, the strong-coupling analysis allows to obtain the location of the phase boundary analytically. For general model parameters, we determine the phase diagram and investigate the thermodynamics using numerical renormalization group calculations. In the singlet phase close to the quantum phase transtion, the entropy is quenched in two steps: first the two Ising-coupled spins form a magnetic mini-domain which is, in a second step, screened by a Kondoesque collective resonance in an effective solitonic Fermi sea. In addition, we present a flow equation analysis which provides a different mapping of the two-impurity model to a generalized single-impurity Anderson model in terms of fully renormalized couplings, which is applicable for the whole range of model parameters.
Garst Markus
Kehrein Stefan
Pruschke Thomas
Rosch Achim
Vojta Matthias
No associations
LandOfFree
Quantum phase transition of Ising-coupled Kondo impurities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Quantum phase transition of Ising-coupled Kondo impurities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quantum phase transition of Ising-coupled Kondo impurities will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-216429