Analysis of the first electron-removal states of using polarization dependent angle-resolved photoelectron spectroscopy

Abstract:

The first electron-removal states of the layered cuprate Ba₂Cu₃O₄Cl₂ were measured using angle-resolved photoelectron spectroscopy. The symmetry and energy-momentum relations of the lowest-lying states were determined and interpreted in terms of the motion of a single hole in the two different planar Cu-O subsystems of the Cu₃O₄ plane. One subsystem is antiferromagnetic as in the undoped parent compounds of the high-temperature superconductors and the other is paramagnetic and corresponds to the strongly overdoped case. The data are compared to theoretical results on hole dynamics in two-dimensional antiferromagnetic or paramagnetic spin backgrounds. The lineshape, symmetry and dispersion of the first electron-removal states of Ba₂Cu₃O₄Cl₂ can be described in terms of Zhang-Rice singlets within a single band model. The photohole lifetime in the paramagnetic subsystem of the Cu₃O₄ plane is much smaller than with an antiferromagnetic spin background.