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

Abstract

We have identified a set of electronic states with a one-dimensional dispersion in the $\ensuremath{\Gamma}=(0,0)$ to ${M}_{1}=(\ensuremath{\pi},0)$ direction crossing the Fermi surface at one point ${k}_{F}=0.2\ifmmode\pm\else\textpm\fi{}0.03\ensuremath{\pi}$ 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.