Nematic quantum criticality in a 2+1-dimensional metal

TKM Institutsseminar

Vortragender:

Samuel Lederer

Datum:

03.09.2015 12:30

Ort:

Raum 10.01, Geb. 30.23 (Physikhochhaus), Campus Süd

Zugehörigkeit:

Stanford University

Gastgeber:

Prof. J. Schmalian

Abstract

Evidence continues to mount that quantum critical points lie beneath the superconducting “dome” of both the iron-based and cuprate high temperature superconductors. Further, these putative critical points appear intimately related to anomalous properties of both the superconducting and normal (metallic) states of these materials. We consider a model for a quantum critical point in a 2+1-dimensional metal with an Ising nematic order parameter, which captures the spontaneous breaking of fourfold rotational symmetry known to occur in the above materials. We simulate this model using numerically exact, sign-problem-free Quantum Monte Carlo techniques, and find evidence of a new strongly coupled fixed point with nontrivial scaling exponents. At this fixed point, the fermions are strongly, perhaps singularly renormalized, consistent with the expected breakdown of Fermi liquid theory.