Valence band electronic structure of Nb2Pd1.2Se5 and Nb2Pd0.95S5 superconductors

We present a comparative study of our valence band photoemission results on Nb2Pd1.2Se5 and Nb2Pd0.95S5 superconductors which are supported by our DFT based electronic structure calculations. We observe that the VB spectra of both the compounds are qualitatively similar, except for some slight differences in the binding energy positions of all the features. This could be due to the unequal electronegativities of Se and S atom. The calculated density of states (DOS) reveals that the VB features are mainly composed of Pd-Se/S hybridized states. The nature of DOS originating from the distinctly coordinated Pd atoms is different. Further, various Pd-4d and Nb-4d states crossing the Fermi level (Ef) signifies the multiband character of these compounds. In addition, we find a temperature dependent pseudogap in Nb2Pd0.95S5 which is absent in Nb2Pd1.2Se5.