Sodium iridate
 Crystal structure of sodium iridium oxide Na 3Ir 3O 8. Cyan spheres show the Ir hyperkagome network; red spheres are oxygen atoms; polyhedra indicate two Na coordination environments. | |
| Properties | |
|---|---|
| Na 3Ir 3O 8 | |
| Molar mass | 773.61 g/mol |
| Density | 7.50 g/cm3[1] |
| Structure | |
| cubic[2] | |
| P4132 (No. 213)[2] | |
Formula units (Z) |
4[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Sodium iridate (chemical formula Na3Ir3O8) is a sodium–iridium oxide that is geometrically frustrated, making it a strongly spin–orbit-coupled transition metal oxide.[3] It is described as a hyperkagome iridate related to Na4Ir3O8, whose hyperkagome lattice is a three-dimensional network of corner-sharing triangular units.[4] Na3Ir3O8 is described as a 1/3-doped analogue of Na4Ir3O8 (average Ir valence ≈ +4.33) and as semimetallic compared with the more insulating hyperkagome parent compound.[3][5]
Structure
[edit]Hyperkagome iridates are discussed as spinel-related (ordered-spinel) materials in which the Ir sublattice forms a three-dimensional network of corner-sharing triangles (the hyperkagome lattice).[5][4] The hyperkagome can be viewed as a "deleted" pyrochlore-type network obtained by removing one-quarter of sites from a pyrochlore lattice.[4][5] In iridates with Ir4+ (5d5), strong spin–orbit coupling entangles spin and t2g orbital character into effective Jeff = 1/2 moments, which is often used to motivate spin-liquid proposals for the hyperkagome lattice.[5][3] Na3Ir3O8 is described as a chiral, frustrated hyperkagome system and is commonly discussed as a doped member within the Na4−xIr3O8 family. Partial Na deintercalation from Na4Ir3O8 can lead to a doped hyperkagome with Na3Ir3O8 as an end member.[3][5]
Physical properties
[edit]Na3Ir3O8 demonstrates strong spin–orbit coupling combined with lattice-driven electronic-structure effects (including distortion-induced molecular orbitals in the hyperkagome setting).[3][5] Because it combines a frustrated lattice with strong spin–orbit coupling and chiral structure, it has been suggested as a platform to explore unconventional electronic transport, including possible topological contributions.[3]
See also
[edit]References
[edit]- ↑ "Na3Ir3O8 (Na4Ir3O8) Crystal Structure". SpringerMaterials. sd_1728111. Retrieved 19 December 2025.
- 1 2 3 4 Takayama, Tomohiro; Yaresko, Alexander; Matsumoto, Akiyo; Nuss, Jürgen; Ishii, Kenji; Yoshida, Masahiro; Mizuki, Junichiro; Takagi, Hidenori (2014). "Spin-orbit coupling induced semi-metallic state in the 1/3 hole-doped hyper-kagome Na3Ir3O8". Scientific Reports. 4: 6818. doi:10.1038/srep06818. PMC 4212231.
- 1 2 3 4 5 6 Rau, Jeffrey G.; Lee, Eric Kin-Ho; Kee, Hae-Young (2016). "Spin-Orbit Physics Giving Rise to Novel Phases in Correlated Systems: Iridates and Related Materials". Annual Review of Condensed Matter Physics. 7: 195–221. arXiv:1507.06323. doi:10.1146/annurev-conmatphys-031115-011319.
- 1 2 3 Zhou, Yi; Kanoda, Kazushi; Ng, Tai-Kai (2017). "Quantum spin liquid states". Reviews of Modern Physics. 89 025003. arXiv:1607.03228. doi:10.1103/RevModPhys.89.025003.
- 1 2 3 4 5 6 Mendels, Philippe; Bert, Fabrice (2016). "Quantum kagome frustrated antiferromagnets: One route to quantum spin liquids". Comptes Rendus Physique. 17 (3–4): 455–470. doi:10.1016/j.crhy.2015.12.001.