High-pressure GaAs Structure: AB_oI4_44_a_b-001
| Prototype | AsGa |
| AFLOW prototype label | AB_oI4_44_a_b-001 |
| ICSD | 43950 |
| Pearson symbol | oI4 |
| Space group number | 44 |
| Space group symbol | $Imm2$ |
| AFLOW prototype command |
aflow --proto=AB_oI4_44_a_b-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak z_{1}, \allowbreak z_{2}$ |
- This is a high-pressure phase of GaAs, stable above 24 GPa. The experimental data used here was taken at a pressure of 28.1 GPa. Without loss of generality we can take $z_{1}=0$. When $a=b$ and $z_{2}=z_{1}+1/4$ this structure becomes the $\beta$–Sn (A5) structure.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}- \frac{1}{2}c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $z_{1} \, \mathbf{a}_{1}+z_{1} \, \mathbf{a}_{2}$ | = | $c z_{1} \,\mathbf{\hat{z}}$ | (2a) | As I |
| $\mathbf{B_{2}}$ | = | $\left(z_{2} + \frac{1}{2}\right) \, \mathbf{a}_{1}+z_{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}b \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ | (2b) | Ga I |
References
- S. T. Weir, Y. K. Vohra, C. A. Vanderborgh, and A. L. Ruoff, Structural phase transitions in GaAs to 108 GPa, Phys. Rev. B 39, 1280–1285 (1989), doi:10.1103/PhysRevB.39.1280.
Found in
- P. Villars and L. Calvert, Pearson's Handbook of Crystallographic Data for Intermetallic Phases (ASM International, Materials Park, OH, 1991), 2nd edn.
Prototype Generator
aflow --proto=AB_oI4_44_a_b --params=$a,b/a,c/a,z_{1},z_{2}$