Quenched Disorder in the Triangular Lattice Antiferromagnet YbZn$_2$GaO$_5$
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866911061146337280 |
|---|---|
| author | Zhao, Leshan Chen, Tong Stone, Matthew B. Zhang, Qiang Sarkis, Colin L. Koohpayeh, S. M. Broholm, Collin |
| author_facet | Zhao, Leshan Chen, Tong Stone, Matthew B. Zhang, Qiang Sarkis, Colin L. Koohpayeh, S. M. Broholm, Collin |
| contents | We investigate the crystal electric field (CEF) excitations of Yb$^{3+}$ ions in powder samples of the triangular-lattice rare-earth-based antiferromagnet YbZn$_2$GaO$_5$ using inelastic neutron scattering (INS). Three CEF excitations from the ground-state Kramers doublet were observed, each exhibiting significant broadening beyond instrumental resolution. Combining temperature-dependent INS and neutron powder diffraction, we identify a significant static contribution to this broadening and attribute it to heterogeneous coordination of Yb$^{3+}$ ions due to Ga$^{3+}$/Zn$^{2+}$ site mixing. Rietveld refinement of neutron powder diffraction indicates that 35% of Ga occupies the Zn site and 60% of Zn occupies the Ga site. We show with a point charge model for the CEF Hamiltonian that heterogeneous coordination of Yb$^{3+}$ ions leads to broadened CEF peaks. First-principles calculations demonstrate that the random Ga$^{3+}$/Zn$^{2+}$ distribution can produce the distortions of the YbO$_6$ octahedra observed from neutron diffraction. Because the documented heterogeneity will extend to exchange interactions, our results suggest that disorder is a significant factor in the unusual magnetism previously reported in YbZn$_2$GaO$_5$, including broad low-energy magnetic excitations and the absence of magnetic ordering down to 0.3K. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_12592 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Quenched Disorder in the Triangular Lattice Antiferromagnet YbZn$_2$GaO$_5$ Zhao, Leshan Chen, Tong Stone, Matthew B. Zhang, Qiang Sarkis, Colin L. Koohpayeh, S. M. Broholm, Collin Strongly Correlated Electrons We investigate the crystal electric field (CEF) excitations of Yb$^{3+}$ ions in powder samples of the triangular-lattice rare-earth-based antiferromagnet YbZn$_2$GaO$_5$ using inelastic neutron scattering (INS). Three CEF excitations from the ground-state Kramers doublet were observed, each exhibiting significant broadening beyond instrumental resolution. Combining temperature-dependent INS and neutron powder diffraction, we identify a significant static contribution to this broadening and attribute it to heterogeneous coordination of Yb$^{3+}$ ions due to Ga$^{3+}$/Zn$^{2+}$ site mixing. Rietveld refinement of neutron powder diffraction indicates that 35% of Ga occupies the Zn site and 60% of Zn occupies the Ga site. We show with a point charge model for the CEF Hamiltonian that heterogeneous coordination of Yb$^{3+}$ ions leads to broadened CEF peaks. First-principles calculations demonstrate that the random Ga$^{3+}$/Zn$^{2+}$ distribution can produce the distortions of the YbO$_6$ octahedra observed from neutron diffraction. Because the documented heterogeneity will extend to exchange interactions, our results suggest that disorder is a significant factor in the unusual magnetism previously reported in YbZn$_2$GaO$_5$, including broad low-energy magnetic excitations and the absence of magnetic ordering down to 0.3K. |
| title | Quenched Disorder in the Triangular Lattice Antiferromagnet YbZn$_2$GaO$_5$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2507.12592 |