Strongly Enhanced Superconductivity in Coupled t-J Segments.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• The t-J Hamiltonian is crucial for understanding strongly correlated electron systems, particularly in copper-oxide materials.
• Superconductivity in uniform 1D t-J models typically requires unphysically large exchange coupling constants (J/t > 3).

Purpose of the Study:

• To investigate the phase diagram of the 1D t-J chain with periodic hopping modulation.
• To determine if periodic modulation can stabilize superconductivity within a physically relevant parameter regime.

Main Methods:

• Utilized the density-matrix renormalization group (DMRG) method.
• Analyzed the phase diagram as a function of electron filling and modulation parameters.

Main Results:

• Periodic hopping modulation drastically reduces the critical coupling for superconductivity to J/t ~ 1/3.
• The phase diagram reveals metallic, insulating, and phase-separated regions alongside superconductivity.
• Demonstrated that coupling t-J segments can stabilize superconducting states.

Conclusions:

• Periodic modulation offers a viable pathway to achieve superconductivity in 1D t-J models under realistic conditions.
• Coupled-segment models, like modulated chains and ladders, are promising for stabilizing superconductivity in strongly correlated systems.