Applied Physics Letters · 2014 · 27 citations · 20 references
Natural SciencesChemistryPhysicsCondensed Matter PhysicsInorganic ChemistrySemiconductor MaterialsAb Initio MethodsDensity Functional TheoryElectronic Band StructureElectronic StructureMolecular Orbital TheoryWide Band Gap SemiconductorsBand GapBand Gap EnergyElectronic Band GapSoft X-ray SpectroscopyValence Band StructureValence-band SpectroscopyX-ray Absorption Spectroscopy
Electronic structures of Pb(Pd0.9T0.1)O2 (T = Mn, Co) spin gapless semiconductors have been investigated by employing soft X-ray absorption spectroscopy (XAS) and photoemission spectroscopy (PES). The valence states of Co and Mn ions are found to be mixed-valent (∼2.7) and tetravalent, respectively. The measured valence-band PES and O 1s XAS spectra show that both PbPdO2 and PbPd0.9Co0.1O2 are small-gap semiconductors. This finding is supported by the calculated band structures, obtained in the density functional theory with the modified Becke-Johnson potential (mBJ) scheme. This work also shows evidence for the existence of the phase separation in Mn-substituted PbPd0.9Mn0.1O2.
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