Photoemission Study of La8?xSrxCu8O20: Impact of the Charge and Spin Density Waves on the Electronic Structure

We report a photoemission study of La8-xSrxCu8O20 which shows antiferromagnetic (AFM), weakly ferromagnetic (WFM), and paramagnetic (PM) phases. All the samples in the AFM, WFM or PM phases are found to have a sharp Fermi edge with finite density of states at the Fermi level (EF), indicating the metallic nature of the samples at different doping and temperatures studied. In the WFM and AFM phases, the spectral weight near the EF (up to ∼-200 meV) is partially suppressed. In the valence band spectra, the Cu 3d and O 2p derived states around ∼-5 and ∼-2.5 eV show different spectral weights in different magnetic phases. The observed changes in the electronic structure can be due to formation of the charge and/or spin density waves causing the anomalies in the electronic and magnetic transport properties of this system.