Numerical study of ferromagnetic fluctuations and pairing correlations in the single-band Hubbard model on the triangular lattice

Abstract

We perform a numerical study using both determinantal and constrain path Monte Carlo methods to investigate the magnetic and pairing properties of the single-band Hubbard model on the triangular lattice. We find that the system in the filling region $⟨n⟩=1.5--1.85$ shows a short-ranged ferromagnetic correlation, and the on-site Coulomb interaction tends to strengthen ferromagnetic fluctuation slightly. It is shown that the large density of states near the Van Hove singularity point plays an important role in the enhancement of ferromagnetic fluctuation. In the ferromagnetic region, we observe that the $f$-wave pairing correlation tends to increase faster than other pairing correlations. However, it is subtle to stabilize the $f$-wave pairing since the effective pairing interaction was found to be very small.