To shed light into the pairing mechanism of possible spin triplet superconductors ${(\text{TMTSF})}_{2}X$ and ${\text{Sr}}_{2}{\text{RuO}}_{4}$ , we study the competition among various spin singlet and triplet pairing channels in the Hubbard model by calculating the pairing interaction vertex using the ground state quantum Monte Carlo technique. We model ${(\text{TMTSF})}_{2}X$ by a quarter-filled quasi-one-dimensional (quasi-1D) Hubbard model, and the $\ensuremath{\gamma}$ band of ${\text{Sr}}_{2}{\text{RuO}}_{4}$ by a two-dimensional (2D) Hubbard model with a band filling of $\ensuremath{\sim}4∕3$. For the quasi-1D system, we find that triplet $f$ -wave pairing not only dominates over the triplet $p$ wave in agreement with the spin fluctuation theory, but also looks unexpectedly competitive against $d$ waves. For the 2D system, although the results suggest the presence of an attractive interaction in the triplet pairing channels, the $d$ -wave pairing interaction is found to be larger than those of the triplet channels.To shed light into the pairing mechanism of possible spin triplet superconductors ${(\text{TMTSF})}_{2}X$ and ${\text{Sr}}_{2}{\text{RuO}}_{4}$, we study the competition among various spin singlet and triplet pairing channels in the Hubbard model by calculating the pairing interaction vertex using the ground state quantum Monte Carlo technique. We model ${(\text{TMTSF})}_{2}X$ by a quarter-filled quasi-one-dimensional (quasi-1D) Hubbard model, and the $\ensuremath{\gamma}$ band of ${\text{Sr}}_{2}{\text{RuO}}_{4}$ by a two-dimensional (2D) Hubbard model with a band filling of $\ensuremath{\sim}4∕3$. For the quasi-1D system, we find that triplet $f$-wave pairing not only dominates over the triplet $p$ wave in agreement with the spin fluctuation theory, but also looks unexpectedly competitive against $d$ waves. For the 2D system, although the results suggest the presence of an attractive interaction in the triplet pairing channels, the $d$-wave pairing interaction is found to be larger than those of the triplet channels.

arXiv:cond-mat/0307553Physical Review BJun 18, 200431 citations

HIGH-SPIN STATES OF 87 Sr

H. W. LI, Xiao Guang Wu, Yong Zheng +16 more

Nuclear Structure in ChinaJan 1, 20130 citations

Spin-Mediated Electron Pairing II

Frederick J. Mayer

International Journal of Physics Study and ResearchMar 18, 20240 citations

Spin singlet and triplet superconductivity in the extended Hubbard model with anisotropic exchange interaction

Yoshiki Hori, Akira Goto

We study the effect of the nearest neighbor anisotropic exchange interaction on superconductivity in extended Hubbard model in a square lattice. This Hamiltonian is one of a base model to describe various effects on triplet superconductors, e.g. Sr 2 RuO 4 , because the ferromagnetic exchange is advantagous for triplet pairing. Within a one-band meanfield approximation, we calculate the critical temperatures of spin singlet and triplet superconductivity. We obtain a phase diagram in the longitudinal vs transverse exchange couplings and we show how the stable pairing state is controlled by the anisotropy of the exchange interaction.We study the effect of the nearest neighbor anisotropic exchange interaction on superconductivity in extended Hubbard model in a square lattice. This Hamiltonian is one of a base model to describe various effects on triplet superconductors, e.g. Sr 2 RuO 4 , because the ferromagnetic exchange is advantagous for triplet pairing. Within a one-band meanfield approximation, we calculate the critical temperatures of spin singlet and triplet superconductivity. We obtain a phase diagram in the longitudinal vs transverse exchange couplings and we show how the stable pairing state is controlled by the anisotropy of the exchange interaction.

Journal of Physics Conference SeriesMar 1, 20092 citations

Unconventional triplet pairing state in a polarized dipolar Fermi gas

Yuki Endo, Daisuke Inotani, Yoji Ohashi

Bulletin of the American Physical SocietyMar 20, 20130 citations

Spin-triplet f-wave pairing via cyclic exchange in the anisotropic triangular Hubbard model: A route to unconventional superconductivity

Satoshi Nishimoto, Y. Ohta

We investigate the interplay between ferromagnetism and unconventional superconductivity in a two-dimensional anisotropic triangular-lattice Hubbard model using the density-matrix renormalization group (DMRG) method. A novel mechanism for spin-triplet f -wave superconductivity is identified, driven by three-site cyclic-exchange interactions. This mechanism highlights the crucial role of lattice anisotropy and triangular hopping networks in stabilizing ferromagnetic correlations necessary for spin-triplet pairing. The slow decay of pair-correlation functions and their sign change under a π / 3 rotation confirm the dominant f -wave symmetry of the superconducting state. These findings offer a unified theoretical framework for understanding unconventional superconductivity in strongly correlated electron systems, with potential relevance to materials such as Bechgaard salts ( TMTSF ) 2 X , cobalt oxide Na 0 . 35 CoO 2 ⋅ 1 . 3 H 2 O , and layered perovskite Sr 2 RuO 4 . • Identifies a mechanism for spin-triplet superconductivity via three-site cyclic exchange. • Demonstrates f -wave pairing symmetry in a triangular-lattice Hubbard model. • Shows lattice anisotropy promotes ferromagnetism that stabilizes triplet pairing.We investigate the interplay between ferromagnetism and unconventional superconductivity in a two-dimensional anisotropic triangular-lattice Hubbard model using the density-matrix renormalization group (DMRG) method. A novel mechanism for spin-triplet f -wave superconductivity is identified, driven by three-site cyclic-exchange interactions. This mechanism highlights the crucial role of lattice anisotropy and triangular hopping networks in stabilizing ferromagnetic correlations necessary for spin-triplet pairing. The slow decay of pair-correlation functions and their sign change under a π / 3 rotation confirm the dominant f -wave symmetry of the superconducting state. These findings offer a unified theoretical framework for understanding unconventional superconductivity in strongly correlated electron systems, with potential relevance to materials such as Bechgaard salts ( TMTSF ) 2 X , cobalt oxide Na 0 . 35 CoO 2 ⋅ 1 . 3 H 2 O , and layered perovskite Sr 2 RuO 4 . • Identifies a mechanism for spin-triplet superconductivity via three-site cyclic exchange. • Demonstrates f -wave pairing symmetry in a triangular-lattice Hubbard model. • Shows lattice anisotropy promotes ferromagnetism that stabilizes triplet pairing.

Physica C SuperconductivityMay 29, 20250 citations

To shed light into the pairing mechanism of possible spin triplet superconductors

{(\text{TMTSF})}_{2}X

and

{\text{Sr}}_{2}{\text{RuO}}_{4}

, we study the competition among various spin singlet and triplet pairing channels in the Hubbard model by calculating the pairing interaction vertex using the ground state quantum Monte Carlo technique. We model

{(\text{TMTSF})}_{2}X

by a quarter-filled quasi-one-dimensional (quasi-1D) Hubbard model, and the $\ensuremath{\gamma}$ band of

{\text{Sr}}_{2}{\text{RuO}}_{4}

by a two-dimensional (2D) Hubbard model with a band filling of $\ensuremath{\sim}4∕3$. For the quasi-1D system, we find that triplet

f

-wave pairing not only dominates over the triplet

p

wave in agreement with the spin fluctuation theory, but also looks unexpectedly competitive against

d

waves. For the 2D system, although the results suggest the presence of an attractive interaction in the triplet pairing channels, the

d

-wave pairing interaction is found to be larger than those of the triplet channels.