Electronic Structure of La2-xSrxCuO4 in the Vicinity of Superconductor-Insulator Transition

We report on the results of angle-resolved photoemission (ARPES) study of La_{2-x}Sr_xCuO_4 (LSCO) from an optimally doped superconductor (x=0.15) to a slightly doped insulator (x=0.03). Near the superconductor-insulator transition (SIT) $x\sim0.05$, ARPES spectral weight is transferred with $x$ between two components which coexist around the SIT, suggesting a microscopic inhomogeneity of the doped-hole distribution. For the underdoped LSCO ($x\lesssim0.1$), the dispersive band crossing the Fermi level disappears in the $(0,0)-(\pi,\pi)$ direction unlike Bi_2Sr_2CaCu_2O_{8+\delta}. These observations are reconciled with the evolution of holes in the insulator into fluctuating stripes in the superconductor.