Emergence of charge loop current in the geometrically frustrated Hubbard model: A functional renormalization group study

Spontaneous current orders due to odd-parity order parameters have attracted increasing attention in various strongly correlated metals. we discover a spin-fluctuation-driven charge loop current (cLC) mechanism based on the functional renormalization group theory. The present mechanism leads to the ferro-cLC order in a simple frustrated chain Hubbard model. The cLC appears between the antiferromagnetic and d-wave superconducting (dSC) phases. While the microscopic origin of the cLC has a close similarity to that of the dSC, the cLC transition temperature T-cLC can be higher than the dSC one for a wide parameter range. Furthermore, we reveal that the ferro-cLC order is driven by the strong enhancement of the forward scatterings g(2) and g(4) owing to the two dimensionality based on the g-ology language. The present study indicates that the cLC can emerge in metals near the magnetic criticality with geometrical frustration.

Automated summary

The study reveals a spin-fluctuation-driven charge loop current (cLC) mechanism in a simple frustrated chain Hubbard model, leading to the ferro-cLC order between the antiferromagnetic and d-wave superconducting (dSC) phases. The transition temperature T-cLC of cLC can be higher than that of dSC in a wide parameter range. The ferro-cLC order is driven by the enhancement of forward scatterings g(2) and g(4) due to the two dimensionality in metals near the magnetic criticality with geometrical frustration.