Soft X-ray emission and high-resolution photoemission study of quasi-two-dimensional superconductor NaxHfNCl

We have performed soft X-ray emission (SXE) and high-resolution photoemission (PE) spectroscopy to study the electronic structures of β-HfNCl and Na-intercalated HfNCl. Both the PE and SXE spectra of Na0.37HfNCl show an additional structure within the band gap of β-HfNCl, without an apparent shift in the energy position of valence-band features. These results clearly reveal intercalant-induced changes in the electronic structure of the layered nitride chlorides. From these results, we propose non-rigid band like behavior for this system in contrast to generally expected rigid-band filling upon intercalation. [Copyright &y& Elsevier]