Mapping different quantum phases in CuxTiSe2 as a function of Cu intercalation

The 1T-TiSe2 system displays unique quantum phenomena such as charge density wave (CDW), excitonic insulating (EI) state instabilities and superconductivity. Recently, phase separation in the electronic structure of Cu-intercalated TiSe2 was found below the CDW transition temperature (~200 K). Here, we propose to study the domain dependent local structure of CuxTiSe2 through space-resolved x-ray absorption spectroscopy (XAS) to characterize these different phases for their valence electronic states as a function of Cu intercalation. The plan is to study single crystal samples with different fractions of Cu, yielding different CDW patterns, in order to obtain comprehensive information on the phase separation and characteristics of the individual phases in these materials. With the proposed approach we expect to derive a quantitative correlation between the electronic structure, CDW, EI state and superconductivity in 1T-TiSe2.