Nodal quasiparticles and antinodal charge ordering in Ca2-xNaxCuO2Cl2

Understanding the role of competing states in the cuprates is essential for developing a theory for high-temperature superconductivity. We report angle-resolved photoemission spectroscopy experiments which probe the 4a(o) x 4a(o) charge-ordered state discovered by scanning tunneling microscopy in the lightly doped cuprate superconductor Ca2-x NaxCuO2Cl2. Our measurements reveal a marked dichotomy between the real- and momentum-space probes, for which charge. ordering is emphasized in the tunneling measurements and photoemission is most sensitive to excitations near the node of the d-wave superconducting gap. These results emphasize the importance of momentum anisotropy in determining the complex electronic properties of the cuprates and places strong constraints on theoretical models of the charge-ordered state.