Electronic structure of {alpha}{sub {ital t}}-(BEDT-TTF){sub 2}I{sub 3}: A photoemission study
- Materials Physics, Department of Physics, Royal Institute of Technology, S-100 44 Stockholm (Sweden)
- 3. Physikalisches Institut, Universitaet Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart (Germany)
Photoemission experiments have been performed on {ital in} {ital situ} cleaved crystals of the organic superconductor {alpha}{sub {ital t}}-(BEDT-TTF){sub 2}I{sub 3}. Nine distinct features are observed in the valence-band regime with binding energies between 1.4 and 11.2 eV. None of the valence-band structures shows dispersion along the {Gamma}-{ital Z} ({ital k}{sub {ital z}}) direction, i.e., perpendicular to the conducting BEDT-TTF layers. The spectral intensity is zero at, and to within about 0.5 eV below the Fermi level. This is ascribed to the presence of a fairly large band gap in this direction, in agreement with band-structure calculations. The photoemission spectrum of the valence band shows remarkable changes when the photon energy is changed. These changes are qualitatively understood as a cross-section dependence. The observed photon energy dependence suggests that both {ital p} orbitals and the lower-lying {ital s} orbitals of the atoms constituting the BEDT-TTF molecule contribute significantly to the molecular orbitals forming the valence band. Core-level spectroscopy on the I 4{ital d} and S 2{ital p} levels revealed no surface or chemically shifted components. The large width of these core levels is ascribed primarily to phonon broadening, although a contribution from disorder cannot be completely ruled out.
- OSTI ID:
- 249434
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 13 Vol. 52; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photoemission study of monoclinic BaBiO sub 3
Electron states and Fermi surfaces in the organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br