Atomic diffusion due to hyperatomic fluctuation for quasicrystals
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2023
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866909616191832064 |
|---|---|
| author | Nagai, Yuki Iwasaki, Yutaka Kitahara, Koichi Takagiwa, Yoshiki Kimura, Kaoru Shiga, Motoyuki |
| author_facet | Nagai, Yuki Iwasaki, Yutaka Kitahara, Koichi Takagiwa, Yoshiki Kimura, Kaoru Shiga, Motoyuki |
| contents | A quasicrystal is an ordered but non-periodic structure understood as a projection from a higher dimensional periodic structure. Some physical properties of quasicrystals are different from those of conventional solids. An anomalous increase in heat capacity at high temperatures has been discussed for over two decades as a manifestation of a hidden high dimensionality of quasicrystals. A plausible candidate for this origin has been phason, which has excitation modes originating from additional degrees of freedom in the higher-dimensional lattice. However, most theoretical studies on phasons have used toy models. A theoretical study of the heat capacity of realistic quasicrystals or their approximants has yet to be conducted because of the huge computational complexity. To bridge this gap between experiment and theory, we show experiments and molecular simulations on the same material, an Al--Pd--Ru quasicrystal, and its approximants. We show that at high temperatures, aluminum atoms diffuse with discontinuous-like jumps, and the diffusion paths of the aluminum can be understood in terms of jumps corresponding to hyperatomic fluctuations in six-dimensional space. It is concluded that the anomaly in the heat capacity of quasicrystals arises from extra degrees of freedom due to hyperatomic fluctuations that play a role in diffusive Nambu--Goldstone modes. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2302_14441 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Atomic diffusion due to hyperatomic fluctuation for quasicrystals Nagai, Yuki Iwasaki, Yutaka Kitahara, Koichi Takagiwa, Yoshiki Kimura, Kaoru Shiga, Motoyuki Materials Science Disordered Systems and Neural Networks A quasicrystal is an ordered but non-periodic structure understood as a projection from a higher dimensional periodic structure. Some physical properties of quasicrystals are different from those of conventional solids. An anomalous increase in heat capacity at high temperatures has been discussed for over two decades as a manifestation of a hidden high dimensionality of quasicrystals. A plausible candidate for this origin has been phason, which has excitation modes originating from additional degrees of freedom in the higher-dimensional lattice. However, most theoretical studies on phasons have used toy models. A theoretical study of the heat capacity of realistic quasicrystals or their approximants has yet to be conducted because of the huge computational complexity. To bridge this gap between experiment and theory, we show experiments and molecular simulations on the same material, an Al--Pd--Ru quasicrystal, and its approximants. We show that at high temperatures, aluminum atoms diffuse with discontinuous-like jumps, and the diffusion paths of the aluminum can be understood in terms of jumps corresponding to hyperatomic fluctuations in six-dimensional space. It is concluded that the anomaly in the heat capacity of quasicrystals arises from extra degrees of freedom due to hyperatomic fluctuations that play a role in diffusive Nambu--Goldstone modes. |
| title | Atomic diffusion due to hyperatomic fluctuation for quasicrystals |
| topic | Materials Science Disordered Systems and Neural Networks |
| url | https://arxiv.org/abs/2302.14441 |