Effect of Doping on the Electron Spectral Function of One-Dimensional Spin-Charge-Well-Separated Systems

The electron spectral function has been studied based on a model suitable for one-dimensional (1D) systems with spin and charge degrees of freedom well-separated. The result can permit a qualitative description of the spin-charge separated spectral feature observed in 1D cuprates. We find that the electron chemical potential shifts downward rapidly with hole doping, making the separated spectral feature harder and harder to be entirely detected in an angle-resolved photoemission (ARPES) measurement, which explains the ARPES result strangely observed in the 1/4-filled Cu–O chains in PrBa2Cu4O8. Additionally, doping evolution of the spectral function is found to show rich physics, and an essential feature is that a new coherent band gradually appears with hole doping just about the top of the lower Hubbard band, which is very similar to that observed in two-dimensional cuprates.