Related Experiment Videos
Tunneling state anisotropy in a single grain decagonal quasicrystal
F Bert1, G Bellessa, B Grushko
1Laboratoire de Physique des Solides, Université Paris-Sud, Bâtiment 510, 91405 Orsay, France.
Physical Review Letters
|July 5, 2002
Summary
Low-temperature measurements reveal tunneling states (TSs) in Al-Ni-Co quasicrystals. The study shows TSs are generated by the quasicrystalline structure, with anisotropic phonon-TS coupling.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Acoustics
Background:
- Quasicrystals, such as Al-Ni-Co, exhibit unique atomic structures.
- Understanding low-temperature properties of quasicrystals is crucial for materials science.
- Tunneling states (TSs) are quantum phenomena observed in amorphous solids.
Purpose of the Study:
- To investigate sound velocity variations in a decagonal quasicrystal (Al-Ni-Co) at low temperatures.
- To explore the nature and origin of tunneling states (TSs) in quasicrystalline materials.
- To determine the relationship between quasicrystalline structure and TSs.
Main Methods:
- Low-temperature measurements (20 mK to 20 K).
- Utilized 70 MHz acoustic shear waves.
- Analyzed wave propagation parallel and perpendicular to quasicrystalline planes with two polarizations.
Main Results:
- Observed sound velocity variations indicating the presence of tunneling states (TSs).
- Demonstrated a significant difference in phonon-TS coupling for different wave polarizations.
- Revealed strong anisotropy in the orientation distribution of TSs within the sample.
Conclusions:
- Tunneling states (TSs) are directly generated by the quasicrystalline structure itself.
- The observed anisotropy provides evidence for the structural origin of TSs.
- Acoustic measurements offer insights into the quantum properties of quasicrystals.