Comment on "Evidence for a small hole pocket in the Fermi surface of   underdoped YBa2Cu3Oy; [arXiv:1409.2788v1]"
  N. Doiron-Leyraud et al. in [1] report on the experimental observation of small holes pockets in the energy spectrum of YBa2Cu3Oy (YBCO) coming below the transition into the charge ordered (CO) phase as a result of a Fermi surface (FS) reconstruction. We comment that their results seem to be more consistent with a unidirectional charge density wave (CDW) vector direction of which alternates along the c-axis between neighboring CuO2 -planes. 
Lev P. Gor'kov and Gregory B. Teitel'baum
cond-mat.supr-con cond-mat.str-el