Quantum Paramagnet in a π Flux Triangular Lattice Hubbard Model.

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Theoretical Physics

Background:

• Stabilizing magnetically disordered quantum states is crucial for understanding exotic phenomena.
• Charge fluctuations often compete with magnetic order, complicating theoretical models.
• The interplay between charge and spin degrees of freedom is key in many novel materials.

Purpose of the Study:

• To propose and analyze the π flux triangular lattice Hubbard model (π THM) as a controllable system for stabilizing quantum paramagnetic states.
• To investigate the phase diagram of the π THM, particularly the quantum paramagnetic domain.
• To establish connections between the π THM and established models like the Heisenberg-Kitaev model.

Main Methods:

• Theoretical proposal of the π flux triangular lattice Hubbard model (π THM).
• Analysis of the model's phase diagram, identifying quantum paramagnetic, Dirac semimetal, and Néel ordered phases.
• Generalization of Klein duality to tight-binding models and mapping to the Heisenberg-Kitaev model.

Main Results:

• Identification of a quantum paramagnetic domain in the π THM for intermediate Hubbard interaction (U).
• Characterization of the model's boundaries: a Dirac semimetal at weak coupling and 120° Néel order at strong coupling.
• Demonstration of a mapping to the Heisenberg-Kitaev model in the strong coupling limit via generalized Klein duality.

Conclusions:

• The π THM serves as a viable theoretical platform for stabilizing magnetically disordered quantum states alongside charge fluctuations.
• The model exhibits a rich phase diagram with potential for hosting exotic spin liquid ground states.
• The established duality provides a pathway for numerical investigations of these complex quantum states.