Pseudogap and Mott physics on a frustrated lattice

The pseudogap spans a large part of the phase diagram of hole-doped superconducting cuprates, so it is important to understand its origin. Cluster generalizations of dynamical mean-field theory suggest that it can be a consequence of Mott physics [1] and super-exchange without large antiferromagnetic correlation lengths. We explore this possibility by studying this phenomenon on the triangular lattice using Dynamical Cluster Approximation (DCA). On that lattice, frustration keeps the antiferromagnetic correlation length short. This approach allows us to obtain the size-converged results down to relatively low temperatures. We find that a pseudogap does appear and is separated from the correlated Fermi liquid by a first-order “Sordi” transition, a transition continuously connected to the Mott transition. We conclude that Mott physics and associated short-range anti-ferromagnetic correlations lead to a pseudogap.

 

[1] G. Sordi, et al. Scientific Reports, 2, 547 (2012)