I-centered vs F-centered orthorhombic symmetry and negative thermal expansion of the charge density wave of EuAl2Ga2
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866908336974200832 |
|---|---|
| author | Agarwal, Harshit Kotla, Surya Rohith Noohinejad, Leila Bag, Biplab Eisele, Claudio Ramakrishnan, Sitaram Tolkiehn, Martin Paulmann, Carsten Thamizhavel, Arumugam Ramakrishnan, Srinivasan van Smaalen, Sander |
| author_facet | Agarwal, Harshit Kotla, Surya Rohith Noohinejad, Leila Bag, Biplab Eisele, Claudio Ramakrishnan, Sitaram Tolkiehn, Martin Paulmann, Carsten Thamizhavel, Arumugam Ramakrishnan, Srinivasan van Smaalen, Sander |
| contents | Together with EuGa4 and EuAl4, EuAl2Ga2 belongs to the BaAl4 structure type with space group symmetry I4/mmm. EuAl2Ga2 develops an incommensurate charge density wave (CDW) at temperatures below TCDW = 51 K. On the basis of temperature dependent single-crystal X-ray diffraction (SXRD) data, the incommensurately modulated CDW crystal structure of EuAl2Ga2 is determined to possess orthorhombic superspace symmetry Immm(00g)s00. This symmetry is different from the orthorhombic Fmmm based symmetry of the CDW state of EuAl4. Nevertheless, both symmetries Immm(00g)s00 and Fmmm(00g)s00 lead to the same conclusion, that the CDW is supported by the layers of Al1 type atoms, while the Eu and Al2 or Ga atoms are not directly involved in CDW formation. The different symmetries of the CDW states of EuAl4 and EuAl2Ga2, as well as the observation of negative thermal expansion in the CDW state of EuAl2Ga2 might be explained by the effects of Ga substitution in the latter compound. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_13563 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | I-centered vs F-centered orthorhombic symmetry and negative thermal expansion of the charge density wave of EuAl2Ga2 Agarwal, Harshit Kotla, Surya Rohith Noohinejad, Leila Bag, Biplab Eisele, Claudio Ramakrishnan, Sitaram Tolkiehn, Martin Paulmann, Carsten Thamizhavel, Arumugam Ramakrishnan, Srinivasan van Smaalen, Sander Strongly Correlated Electrons Materials Science Together with EuGa4 and EuAl4, EuAl2Ga2 belongs to the BaAl4 structure type with space group symmetry I4/mmm. EuAl2Ga2 develops an incommensurate charge density wave (CDW) at temperatures below TCDW = 51 K. On the basis of temperature dependent single-crystal X-ray diffraction (SXRD) data, the incommensurately modulated CDW crystal structure of EuAl2Ga2 is determined to possess orthorhombic superspace symmetry Immm(00g)s00. This symmetry is different from the orthorhombic Fmmm based symmetry of the CDW state of EuAl4. Nevertheless, both symmetries Immm(00g)s00 and Fmmm(00g)s00 lead to the same conclusion, that the CDW is supported by the layers of Al1 type atoms, while the Eu and Al2 or Ga atoms are not directly involved in CDW formation. The different symmetries of the CDW states of EuAl4 and EuAl2Ga2, as well as the observation of negative thermal expansion in the CDW state of EuAl2Ga2 might be explained by the effects of Ga substitution in the latter compound. |
| title | I-centered vs F-centered orthorhombic symmetry and negative thermal expansion of the charge density wave of EuAl2Ga2 |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2408.13563 |