Observation of symmetry-distinct states proximate to the Fermi level in a high-Tc cuprate family

Current understanding of cuprate superconductivity is based exclusively on an effective one-band electronic band structure formed by states of in-plane dx2-y2 symmetry. By studying the La-based cuprates with polarization-dependent angle-resolved photoemission spectroscopy, here we uncovered another group of states of distinct c-axis symmetry that coexists with the dx2-y2-symmetry states near the Fermi level and eluded previous detection. As functions of momentum and doping, these new states show overall different dispersion relations yet a qualitatively similar low-energy (pseudo)gapping behavior as the dx2-y2-symmetry states, until they become closely degenerate above $\sim$20{\%} doping.