Holographic fermionic system with dipole coupling on Q-lattice

TL;DR

This paper develops a holographic fermionic model on Q-lattices with dipole coupling, revealing how the Mott gap forms and spectral weight transfers, influenced by lattice parameters and temperature, with anisotropic effects observed.

Contribution

It introduces a holographic model for fermions on Q-lattices with dipole coupling, analyzing gap formation, spectral transfer, and anisotropic phases in a unified framework.

Findings

Mott gap opens more easily in insulating backgrounds with smaller coupling.

Lattice parameters significantly affect the gap width and transition points.

Anisotropic peaks indicate direction-dependent metallic and insulating phases.

Abstract

We construct a holographic model for a fermionic system on Q-lattice and compute the spectral function in the presence of a dipole coupling. Both key features of doped Mott insulators, the dynamical generation of a gap and spectral weight transfer, are observed when adjusting the value of the coupling parameter $p$. Of particular interest is that when the background is in a deep insulating phase, the Mott gap opens much easier with a smaller coupling parameter in comparison with a metallic background. The effects of lattice parameters on the width of the gap $\Delta/\mu$ are studied and a turning point is observed near the critical regime of metal-insulator transitions of the background. Furthermore, the temperature dependence of the spectral function is studied. Finally, we also observe that the anisotropic Q-lattice generates anisotropic peaks with different magnitudes, indicating that insulating and metallic phases arise in different directions.