Doped Mott insulator on Penrose tiling

TL;DR

This paper investigates how doping affects a Mott insulator on a Penrose tiling, revealing unique charge distributions and a site-dependent pseudogap caused by strong correlations and quasiperiodicity.

Contribution

It introduces a real-space dynamical mean-field theory approach to study the interplay of quasiperiodicity and strong correlations in doped Mott insulators.

Findings

Charge distribution differs from static mean-field predictions.

Site-dependent gap appears above the Fermi energy.

Emergence of a real-space pseudogap linked to Mott physics.

Abstract

We study the effect of carrier doping to the Mott insulator on the Penrose tiling, aiming at clarifying the interplay between quasiperiodicity and strong electron correlations. We numerically solve the Hubbard model on the Penrose-tiling structure within a real-space dynamical mean-field theory, which can deal with a singular self-energy necessary to describe the Mott insulator and spatial inhomogeneity. We find that the strong correlation effect produces a charge distribution unreachable by a static mean-field approximation. In a small doping region, the spectrum shows a site-dependent gap just above the Fermi energy, which is generated by a singularly large self-energy emergent from the Mott physics and regarded as a real-space counterpart of the momentum-dependent pseudogap observed in a square-lattice Hubbard model.