Quantum paramagnet in a $\pi$ flux triangular lattice Hubbard model

TL;DR

This paper introduces the $ ext{pi}$ flux triangular lattice Hubbard model as a platform to explore quantum disordered states, revealing a quantum paramagnetic phase between Dirac semi-metal and N{é}el order, and connecting to the Heisenberg-Kitaev model.

Contribution

It proposes the $ ext{pi}$ flux triangular lattice Hubbard model as a new system to study quantum spin liquids and maps it to the Heisenberg-Kitaev model in the strong coupling limit.

Findings

Identification of a quantum paramagnetic phase at intermediate U

Mapping to the Heisenberg-Kitaev model with specific parameters

Potential for numerical investigation of exotic spin liquid states

Abstract

We propose the $\pi$ flux triangular lattice Hubbard model ($\pi$-THM) as a prototypical setup to stabilize magnetically disordered quantum states of matter in the presence of charge fluctuations. The quantum paramagnetic domain of the $\pi$-THM which we identify for intermediate Hubbard U is framed by a Dirac semi-metal for weak coupling and by 120${}^{\circ}$ N\'eel order for strong coupling. Generalizing the Klein duality from spin Hamiltonians to tight-binding models, the $\pi$-THM maps to a Hubbard model which corresponds to the $(J_H, J_K)=(-1,2)$ Heisenberg-Kitaev model in its strong coupling limit. The $\pi$-THM provides a promising microscopic testing ground for exotic finite-U spin liquid ground states amenable to numerical investigation.