The origin of a${}_{1g}$ and e${}_g$' orderings in Na${}_x$CoO${}_2$

D. Pillay, M. D. Johannes, I. I. Mazin +1

It has often been suggested that correlation effects suppress the small e_g' Fermi surface pockets of NaxCoO_2 that are predicted by LDA, but absent in ARPES measurements. It appea…