A Novel Insulator by Holographic Q-lattices

TL;DR

This paper introduces a holographic model with Q-lattice structure that simulates a novel insulator exhibiting a hard gap, vanishing DC conductivity, and unique optical properties, providing insights into strongly correlated insulating phases.

Contribution

The paper develops a gravity dual model with Q-lattices that captures key features of Mott insulators, including a hard gap and non-Drude optical conductivity behavior.

Findings

Achieves a hard gap in the insulating phase.

Demonstrates vanishing DC conductivity.

Reveals non-Drude optical conductivity characteristics.

Abstract

We construct a bulk geometry with Q-lattice structure, which is implemented by two gauge fields and a coupling between the lattice and the Maxwell field. This gravity dual model can describe a novel insulator which exhibits some key features analogous to Mott insulator. In particular, a hard gap in insulating phase as well as vanishing DC conductivity can be simultaneously achieved. In addition, we discuss the non-Drude behavior of the optical conductivity in low frequency region in insulating phase, which exhibits some novel characteristics different from ordinary Mott insulator.