γ-GaSe Structure: AB_hR4_160_2a_2a-001
| Prototype | GaSe |
| AFLOW prototype label | AB_hR4_160_2a_2a-001 |
| ICSD | 73388 |
| CCDC | 1634184 |
| Pearson symbol | hR4 |
| Space group number | 160 |
| Space group symbol | $R3m$ |
| AFLOW prototype command |
aflow --proto=AB_hR4_160_2a_2a-001
--params=$a, \allowbreak c/a, \allowbreak x_{1}, \allowbreak x_{2}, \allowbreak x_{3}, \allowbreak x_{4}$ |
Other compounds with this structure
InSe
- GaSe takes on a variety of structures depending on the stacking of the Ga$_{2}$Se$_{2}$ layers:
- $\beta$–GaSe is in space group $P6_3/mmc$ #194.
- $\gamma$–GaSe (this structure) is in space group $R3m$ #160.
- $\delta$–GaSe is in space group $P6_{3}mc$ #186.
- $\epsilon$–GaSe is in space group $P\overline{6}m2$ #187.
- There is no ICSD entry for (Kuhn, 1975), so we use the earlier work of (Schubert, 1955).
- Hexagonal settings of this structure can be obtained with the option
--hex.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+\frac{1}{3}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{\sqrt{3}}a \,\mathbf{\hat{y}}+\frac{1}{3}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+\frac{1}{3}c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $x_{1} \, \mathbf{a}_{1}+x_{1} \, \mathbf{a}_{2}+x_{1} \, \mathbf{a}_{3}$ | = | $c x_{1} \,\mathbf{\hat{z}}$ | (1a) | Ga I |
| $\mathbf{B_{2}}$ | = | $x_{2} \, \mathbf{a}_{1}+x_{2} \, \mathbf{a}_{2}+x_{2} \, \mathbf{a}_{3}$ | = | $c x_{2} \,\mathbf{\hat{z}}$ | (1a) | Ga II |
| $\mathbf{B_{3}}$ | = | $x_{3} \, \mathbf{a}_{1}+x_{3} \, \mathbf{a}_{2}+x_{3} \, \mathbf{a}_{3}$ | = | $c x_{3} \,\mathbf{\hat{z}}$ | (1a) | Se I |
| $\mathbf{B_{4}}$ | = | $x_{4} \, \mathbf{a}_{1}+x_{4} \, \mathbf{a}_{2}+x_{4} \, \mathbf{a}_{3}$ | = | $c x_{4} \,\mathbf{\hat{z}}$ | (1a) | Se II |
References
- A. Kuhn, A. Chevy, and R. Chevalier, Crystal Structure and Interatomic Distances in GaSe, phys. stat. sol. (a) 31, 469–475 (1975), doi:10.1002/pssa.2210310216.
- K. Schubert, E. Dörre, and M. Kluge, Zur Kristallchemie der B-Metalle. III. Kristallstruktur von GaSe und InTe, Z. Metallkd. 46, 216–224 (1955), doi:10.1515/ijmr-1955-460312.
First cited in
- H. Eckert, S. Divilov, M. J. Mehl, D. Hicks, A. C. Zettel, M. Esters, X. Campilongo, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 4, Comp. Mat. Sci. 240, 112988 (2024). (doi=10.1016/j.commatsci.2021.110450)
Geometry files
Prototype Generator
aflow --proto=AB_hR4_160_2a_2a --params=$a,c/a,x_{1},x_{2},x_{3},x_{4}$