Strongly enhanced superconductivity in coupled t-J segments

Abstract

The $t-J$ Hamiltonian is one of the cornerstones in the theoretical study of strongly correlated copper-oxide based materials. Using the density matrix renormalization group method we calculate the phase diagram of the one-dimensional (1D) $t-J$ chain in the presence of a periodic hopping modulation, as a prototype of coupled-segment models. While in the uniform 1D $t-J$ model near half-filling superconducting (SC) state dominates only at unphysically large values of the exchange coupling constant $J/t>3$, we show that a small hopping and exchange modulation very strongly reduces the critical coupling to be as low as $J/t\sim 1/3$ -- well within the physical regime. The phase diagram as a function of the electron filling also exhibits metallic, insulating line phases and regions of phase separation. We suggest that a SC state is easily stabilized if $t-J$ segments creating local spin-singlet pairing are coupled to each other -- another example is ladder system.

4 pages + 4 figures; 5 pages + 6 figures

References in corpus (2)

• Direct observation of competition between superconductivity and charge density wave order in YBa2Cu3Oy
• Tomonaga-Luttinger parameters for doped Mott insulators

Cited by in corpus (4)

• Surface energy of the one-dimensional supersymmetric $t-J$ model with unparallel boundary fields
• Enhanced superconductivity and various edge modes in modulated $t$-$J$ chains
• Surface energy of the one-dimensional supersymmetric $t-J$ model with general integrable boundary terms in the antiferromagnetic sector
• On the Bethe states of the one-dimensional supersymmetric t-J model with generic open boundaries