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Quasicrystalline valence bands in decagonal AlNiCo
1Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. erotenberg@lbl.gov
Nature
|August 19, 2000
Summary
Quasicrystals exhibit ordered structures with unique symmetries. Angle-resolved photoemission experiments reveal that their electronic states behave like extended bands, not localized ones, challenging previous assumptions.
Area of Science:
- Materials Science
- Condensed Matter Physics
Background:
- Quasicrystals possess long-range order but lack periodicity, leading to unusual properties.
- Understanding the nature of their valence electronic states (extended vs. localized) is crucial but remains unresolved.
Purpose of the Study:
- To investigate the electronic band structure of quasicrystals.
- To determine if electronic states in quasicrystals are extended or localized.
Main Methods:
- Angle-resolved photoemission spectroscopy (ARPES) experiments.
- Study focused on decagonal Al71.8Ni14.8Co13.4 quasicrystals.
Main Results:
- Observed s-p and d electronic states exhibiting band-like behavior.
- Electronic band structure showed symmetry consistent with the quasiperiodic lattice.
- Dispersing d-bands were found to cross the Fermi level.
- Free-electron-like bands were distributed in momentum space mirroring the surface diffraction pattern.
Conclusions:
- The electronic states in quasicrystals are not dominated by localization.
- Results suggest extended electronic states analogous to those in periodic crystals.
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