Enhanced superconductivity and various edge modes in modulated $t$-$J$ chains

Abstract

We numerically investigate the ground state of the extended $t$-$J$ Hamiltonian with periodic local modulations in one dimension by using the density-matrix renormalization group method. Examining charge and spin excitation gaps, as well as the pair binding energy, with extrapolated results to the thermodynamic limit, we obtain a rich ground-state phase diagram consisting of the metallic state, the superconducting state, the phase separation, and insulating states at commensurate fillings. Compared to the homogeneous 1D $t$-$J$ model, the superconductivity is greatly enhanced and stabilized by the flat-band structure. This superconducting state in quasi-periodic chains shares similar properties with ladder systems: significant negative pair binding energy occurs, and the singlet pairing correlation function dominates with the algebraic decay while the single-particle Green's function and spin correlation function decay exponentially. On the other hand, quasi-periodicity leads to nontrivial topological nature in insulating states, characterized by different integer Chern numbers at different fillings. Due to the interplay among the topology, the interaction, and the 1D confinement, gapless edge modes show strong spin-charge separation and in different regions can relate to different collective modes, which are the charge of a single fermion, the magnon, and the singlet-pair. We also find two interaction driven topological transitions: i) at particle filling $\rho =1/2$, the low-energy edge excitations change from the magnon to singlet-pair, accompanied with pair formation in bulk; and ii) at $\rho =3/4$, while the gapless edge mode remains the charge of a single fermion, there is a gap-closing point and a $\pi$-phase shift in the quasi-particle spectrum.

10 pages,15 figures

References in corpus (35)

• Many-Body Physics with Ultracold Gases
• Berry Phase Effects on Electronic Properties
• A High Phase-Space-Density Gas of Polar Molecules
• Chern Numbers in Discretized Brillouin Zone: Efficient Method of Computing (Spin) Hall Conductances
• Topological States and Adiabatic Pumping in Quasicrystals
• Fermi-Hubbard physics with atoms in an optical lattice
• Ultracold Dipolar Gas of Fermionic ${}^{23}$Na${}^{40}$K Molecules in their Absolute Ground State
• Tunable Superfluidity and Quantum Magnetism with Ultracold Polar Molecules
• Edge states and topological phases in one-dimensional optical superlattices
• A Fermi Degenerate Gas of Polar Molecules
• Spin transport in a tunable Heisenberg model realized with ultracold atoms
• Microscopy of the interacting Harper-Hofstadter model in the few-body limit
• Controlling the accuracy of the density matrix renormalization group method: The Dynamical Block State Selection approach
• Quantum Magnetism with Polar Alkali Dimers
• Ground State Phase Diagram of the $t$-$t^{\prime }$-$J$ model
• Topological Bose-Mott Insulators in a One-Dimensional Optical Superlattice
• Observation of separated dynamics of charge and spin in the Fermi-Hubbard model
• High Temperature Superconductivity in a Lightly Doped Quantum Spin Liquid
• Robust d-wave superconductivity in the square-lattice $t$-$J$ model
• Topological Phase Transitions for Interacting Finite Systems
• Pairing and superconductivity in the flat band: Creutz lattice
• Fractional topological states of dipolar fermions in one-dimensional optical superlattices
• Ground-State Phase Diagram of the 1D t-J model
• Nature of strong hole pairing in doped Mott antiferromagnets
• Quantum phases and topological properties of interacting fermions in one-dimensional superlattices
• Topological nature of magnetization plateaus in periodically modulated quantum spin chains
• Superconducting gap for a 2-leg t-J ladder
• Various Topological Mott insulators in strongly-interacting boson system in one-dimensional superlattice
• Luttinger liquid superlattices: realization of gapless insulating phases
• Topological incommensurate magnetization plateaus in quasi-periodic quantum spin chains
• Interaction induced fractionalization and topological superconductivity in the polar molecules anisotropic $t-J$ model
• Topological Mott Insulator with Bosonic Edge Modes in 1D Fermionic Superlattices
• Fractional Topological States in Quantum Spin Chains with Periodical Modulation
• Strongly enhanced superconductivity in coupled t-J segments
• Singlet pairing and superconductivity in t-J ladders with Mott insulating stripes

Cited by in corpus (2)

• Disorder in interacting quasi-one-dimensional systems: flat and dispersive bands
• Tuning competition between charge order and superconductivity in the square-lattice $t$-$t^{\prime }$-$J$ model