Destruction of the small Fermi surfaces in Na$_x$CoO$_2$ by Na disorder
  We show using density functional calculations that the small $e_g'$ Fermi surfaces in Na$_x$CoO$_2$ are destroyed by Na disorder. This provides a means to resolve the prediction of these sections in band structure calculations with their non-observation in angle resolved photoemission experiments. 
D.J. Singh and Deepa Kasinathan