Electronic quasiparticles in the quantum dimer model

Jul. 08 (Fri.) 2PM, #1323(E6-2. 1st fl.)
Dr. Junhyun Lee, Harvard University

We study a recently proposed quantum dimer model for the pseudogap metal state of the cuprates. The model contains bosonic dimers, representing a spin-singlet valence bond between a pair of electrons, and fermionic dimers, representing a quasiparticle with spin-1/2 and charge +e. By density matrix renormalization group calculations on a long but finite cylinder, we obtain the ground state density distribution of the fermionic dimers for a number of different total densities. From the Friedel oscillations at open boundaries, we deduce that the Fermi surface consists of small hole pockets near (π/2, π/2), and this feature persists up to doping density 1/16. We also compute the entanglement entropy and find that it closely matches the sum of the entanglement entropies of a critical boson and a low density of free fermions. Our results support the existence of a fractionalized Fermi liquid (FL*) in this model.

Contact: Eun Gook Moon, Physics Dept., (egmoon@kaist.ac.kr)