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▲ [15a-B508-4] Observation of electronic band dispersion in polycrystalline PTCDI-C8 thin film
キーワード:Band dispersion
We studied the angle-resolved photoelectron spectroscopy measurements for N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) film. The vacuum-deposited PTCDI-C8 film exhibits polycrystalline structure with most of the crystallites oriented with their ab-plane parallel to the substrate and c-axis perpendicular to the substrate. A clear signature of energy dispersion of the band derived from the highest occupied molecular orbital was observed. While we expect the ARPES spectrum to be a superposition of the band dispersions in all azimuthal directions in ab-plane, the approximate correspondence of the observed dispersion periodicity with the reciprocal lattice length along b-axis (π-π staking direction) likely indicates that the dispersion in this direction is most pronounced. We think this is possibly due to the expected strong in-plane anisotropy of the HOMO band dispersion width. The fundamental physical parameters of the electronic band structure, such as trabsfer integral and the effcetive masses will be later elucidated.