Building a doped Mott system by holography

TL;DR

This paper develops a holographic Q-lattice model that exhibits Mott-like metal-insulator transitions, including a hard gap and metallic behavior at zero temperature, providing insights into doped Mott systems.

Contribution

It introduces an interacting term in a holographic Q-lattice model to simulate Mott-like transitions and explores their properties at finite and zero temperature.

Findings

Transition from metal to insulator as lattice constant increases

Observation of a hard gap in optical conductivity

Presence of a zero-frequency mode with tiny spectral weight at zero temperature

Abstract

We construct a holographic model in the framework of Q-lattices whose dual exhibits metal-insulator transitions. By introducing an interacting term between the Q-lattice and the electromagnetic field in bulk geometry, we find such kind of transition can be Mott-like. The evidences are presented as follows. i) The transition from a metallic phase to an insulating phase occurs when the lattice constant becomes larger. ii) A hard gap in the insulating phase can be manifestly observed in the optical conductivity. Nevertheless, in the zero temperature limit this model exhibits novel metallic behavior, featured by a gap as well as a zero-frequency mode with tiny spectral weight. It implies that our model is dual to a doped Mott system in one dimension where umklapp scattering is frozen at zero temperature. The similarity between this model and some organic linear chain conductors is briefly discussed.