Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 1: Correlated Electrons: Low-dimensional Systems - Models 1

TT 1.11: Talk

Monday, March 26, 2012, 12:15–12:30, H 0104

Anomalous criticality near semimetal-to-superfluid quantum phase transition in a two-dimensional Dirac cone model — •Benjamin Obert¹, So Takei², and Walter Metzner¹ — ¹Max-Planck-Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany — ²Department of Physics, The University of Maryland College Park, MD 20742, USA

We analyse a two-dimensional Dirac Cone model which undergoes a quantum phase transition between a semimetal and a superfluid. The model consists of attractively interacting electrons with a linear dispersion around a single Dirac point. We compute the renormalization group flow for the model and study both ground state and finite temperature properties. The electrons and the order parameter fluctuations exhibit power-law scaling with anomalous scaling dimensions. The quasiparticle weight and the Fermi velocity vanish at the quantum critical point. The order parameter correlation length turns out to be infinite everywhere in the semimetallic ground state.
P. Strack, S. Takei, and W. Metzner, Phys. Rev. B 81, 125103 (2010).
B. Obert, S. Takei, and W. Metzner, Ann. Phys. (Berlin) 523, No.8-9, 621-628 (2011)