Evidence for a second one-dimensional set of states shedding light on the normal phase of high-$T_c$ superconductors

We have identified a set of electronic states with a one-dimensional dispersion in the $\Gamma =(0,0)\mathrm{}$ to $M_1=(\pi ,0)$ direction crossing the Fermi surface at one point $k_F=0.2\mathrm{}\pm 0.03\pi$ by angle-resolved photoemission. The one-dimensional character of these electronic states is demonstrated by missing dispersion along the orthogonal direction, observed in energy-distribution curves, and by $k$-space mapping of the Fermi surface, using angle scanning photoemission. The observed electronic states beyond the well-known large Fermi surface provoke the models based on charge and spin ordering in the ${\mathrm{CuO}}_2$ plane of high-$T_c$ superconductors.