title: Chirality-driven mass enhancement in the kagome Hubbard model.
abstract: We investigate the quasiparticle-mass enhancement in the Hubbard model on the frustrated kagome lattice by using a cluster extension of the dynamical mean-field theory. By analyzing the cluster density matrix, we find a hierarchy of energy scale among charge, spin, and chirality degrees of freedom. A large amount of entropy associated with the chirality is released at a much lower temperature than other energy scales for spin and charge fluctuations, leading to a sharp peak in the specific heat and the single-particle spectrum. The results manifest a generic mechanism of mass enhancement driven by an emergent composite degree of freedom under geometrical frustration.
authors.affiliation: Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Udagawa
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Motome