Absence of Long-Range Order in a Triangular Spin System with Dipolar Interactions

Area of Science:

• Condensed Matter Physics
• Quantum Magnetism

Background:

• The triangular lattice antiferromagnetic Heisenberg model is a key example of frustrated magnets, typically ordering at low temperatures.
• Previous studies using density matrix renormalization group (DMRG) suggested small spin liquid regions under specific conditions (J2/J1 ratio, small dipole tilting angles).

Purpose of the Study:

• To investigate the existence and extent of a quantum paramagnetic phase in the triangular lattice dipolar Heisenberg model.
• To map the phase diagram of this model using advanced computational techniques.

Main Methods:

• Utilizing functional renormalization group (RG) to analyze magnetic instabilities.
• Examining the flow of vertex functions and spin susceptibility down to the lowest RG scales.

Main Results:

• A robust quantum paramagnetic phase was identified in a broad region (θ∈[0,54°)) for dipoles tilted along the lattice diagonal.
• The quantum paramagnetic phase exhibits smooth, continuous RG flow, unlike phases with stripe or spiral order.

Conclusions:

• The discovered wide quantum paramagnetic phase provides a promising avenue for exploring quantum spin liquids.
• This research is particularly relevant for ultracold dipolar molecules as potential candidates for hosting quantum spin liquids.