Volume 102, Number 3, May 2013
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||22 May 2013|
Double occupancy and magnetic susceptibility of the Anderson impurity model out of equilibrium
1 Institut für Theoretische Physik, Universität Göttingen - D-37077 Göttingen, Germany, EU
2 Department of Physics, State University of New York at Buffalo - Buffalo, NY 14260, USA
3 Department of Physics, Georgetown University - Washington, DC 20057, USA
4 Lehrstuhl für Theoretische Physik II, Technische Universität Dortmund - D-44221 Dortmund, Germany, EU
5 Department of Physics, University of Fribourg - CH-1700 Fribourg, Switzerland
Received: 1 February 2013
Accepted: 28 April 2013
We use different numerical approaches to calculate the double occupancy and magnetic susceptibility as a function of a bias voltage in an Anderson impurity model. Specifically, we compare results from the Matsubara voltage quantum Monte Carlo approach (MV-QMC), the scattering states numerical renormalization group (SNRG), and real-time quantum Monte Carlo (RT-QMC), covering Coulomb repulsions ranging from the weak-coupling well into the strong-coupling regime. We observe a distinctly different behavior of the double occupancy and the magnetic response. The former measures charge fluctuations and thus only indirectly exhibits the Kondo scale, while the latter exhibits structures on the scale of the equilibrium Kondo temperature. The Matsubara voltage approach and the scattering states numerical renormalization group yield consistent values for the magnetic susceptibility in the Kondo limit. On the other hand, all three numerical methods produce different results for the behavior of charge fluctuations in strongly interacting dots out of equilibrium.
PACS: 72.15.Qm – Scattering mechanisms and Kondo effect / 73.63.Kv – Quantum dots
© EPLA, 2013
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