  One of the central questions in the cuprate research is the nature of the
"normal state" which develops into high temperature superconductivity (HTSC).
In the normal state of hole-doped cuprates, the existence of charge density
wave (CDW) is expected to shed light on the mechanism of HTSC. With evidence
emerging for CDW order in the electron-doped cuprates, the CDW would be thought
to be a universal phenomenon in high-$T_c$ cuprates. However, the CDW phenomena
in electron-doped cuprate are quite different than those in hole-doped
cuprates. Here we study the nature of the putative CDW in an electron-doped
cuprate through direct comparisons between as-grown and post-annealed
Nd$_{1.86}$Ce$_{0.14}$CuO$_4$ (NCCO) single crystals using Cu $L_3$-edge
resonant soft x-ray scattering (RSXS) and angle resolved photoemission
spectroscopy (ARPES). The RSXS result reveals that the non-superconducting NCCO
shows the same reflections at the wavevector (~1/4, 0, $l$) as like the
reported superconducting NCCO. This superconductivity-insensitive signal is
quite different with the characteristics of the CDW reflection in hole-doped
cuprates. Moreover, the ARPES result suggests that the fermiology cannot
account for such wavevector. These results call into question the universality
of CDW phenomenon in the cuprates.
