Electronic structure of transition metal dichalcogenides PdTe2 and Cu0.05PdTe2 superconductors obtained by angle-resolved photoemission spectroscopy

The layered transition metal chalcogenides have been a fertile land in solid state physics for many decades.Various MX2-type transition metal dichalcogenides,such as WTe2,Ir Te2,and Mo S2,have triggered great attention recently,either for the discovery of novel phenomena or some extreme or exotic physical properties,or for their potential applications.Pd Te2 is a superconductor in the class of transition metal dichalcogenides,and superconductivity is enhanced in its Cuintercalated form,Cu0.05 Pd Te2.It is important to study the electronic structures of Pd Te2 and its intercalated form in order to explore for new phenomena and physical properties and understand the related superconductivity enhancement mechanism.Here we report systematic high resolution angle-resolved photoemission(ARPES) studies on Pd Te2 and Cu0.05 Pd Te2single crystals,combined with the band structure calculations.We present in detail for the first time the complex multi-band Fermi surface topology and densely-arranged band structure of these compounds.By carefully examining the electronic structures of the two systems,we find that Cu-intercalation in Pd Te2 results in electron-doping,which causes the band structure to shift downwards by nearly 16 me V in Cu0.05 Pd Te2.Our results lay a foundation for further exploration and investigation on Pd Te2 and related superconductors.