Anomalously strong near-neighbor attraction in doped 1D cuprate chains

In the cuprates, one-dimensional (1D) chain compounds provide a distinctive opportunity to understand the microscopic physics, owing to the availability of reliable theories. However, progress has been limited by the challenge of controllably doping these materials. We report the synthesis and spectroscopic analysis of the 1D cuprate Ba2-xSrxCuO3+delta over a wide range of hole doping. Our angle-resolved photoemission experiments reveal the doping evolution of the holon and spinon branches. We identify a prominent folding branch whose intensity fails to match predictions of the simple Hubbard model. An additional strong near-neighbor attraction, which may arise from coupling to phonons, quantitatively explains experiments for all accessible doping levels. Considering structural and quantum chemistry similarities among cuprates, this attraction may play a similarly important role in high-temperature cuprate superconductors.

Automated summary

The synthesis and spectroscopic analysis of the 1D cuprate Ba2-xSrxCuO3+delta over a wide range of hole doping was reported. Angle-resolved photoemission experiments revealed the doping evolution of the holon and spinon branches. An additional strong near-neighbor attraction, possibly arising from coupling to phonons, quantitatively explained the experiments for all accessible doping levels. Consideration of structural and quantum chemistry similarities among cuprates suggests that this attraction may also play a crucial role in high-temperature cuprate superconductors.