Face-Centered Orthorhombic La$_{2}$CuO$_{4}$ Structure: AB2C4_oF28_69_a_g_cg-001
| Prototype | CuLa$_{2}$O$_{4}$ |
| AFLOW prototype label | AB2C4_oF28_69_a_g_cg-001 |
| ICSD | 19003 |
| Pearson symbol | oF28 |
| Space group number | 69 |
| Space group symbol | $Fmmm$ |
| AFLOW prototype command |
aflow --proto=AB2C4_oF28_69_a_g_cg-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak x_{3}, \allowbreak x_{4}$ |
- We have found three possible structures for La$_{2}$CuO$_{4}$, the parent compound of the high-temperature cuprate superconductors. All are distortions of the tetragonal K$_{2}$NiF$_{4}$/0201 [(La,Ba)$_{2}$CuO$_{4}$] High-T$_{c}$ Structure, and reduce to that structure with doping of the lanthanum site:
- (Longo, 1973) proposed an face-centered orthorhombic structure (this structure).
- Later other workers, including (Reehuis, 2006) and references therein, proposed a base-centered orthorhombic structure.
- (Reehuis, 2006) found that a base-centered monoclinic structure was a better fit to their neutron diffraction data.
- As the two orthorhombic structures are both referenced in the literature, we present them, as well as the more recent monoclinic structure.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (4a) | Cu I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}$ | = | $\frac{1}{4}b \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (8c) | O I |
| $\mathbf{B_{3}}$ | = | $\frac{1}{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{4}b \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (8c) | O I |
| $\mathbf{B_{4}}$ | = | $- x_{3} \, \mathbf{a}_{1}+x_{3} \, \mathbf{a}_{2}+x_{3} \, \mathbf{a}_{3}$ | = | $a x_{3} \,\mathbf{\hat{x}}$ | (8g) | La I |
| $\mathbf{B_{5}}$ | = | $x_{3} \, \mathbf{a}_{1}- x_{3} \, \mathbf{a}_{2}- x_{3} \, \mathbf{a}_{3}$ | = | $- a x_{3} \,\mathbf{\hat{x}}$ | (8g) | La I |
| $\mathbf{B_{6}}$ | = | $- x_{4} \, \mathbf{a}_{1}+x_{4} \, \mathbf{a}_{2}+x_{4} \, \mathbf{a}_{3}$ | = | $a x_{4} \,\mathbf{\hat{x}}$ | (8g) | O II |
| $\mathbf{B_{7}}$ | = | $x_{4} \, \mathbf{a}_{1}- x_{4} \, \mathbf{a}_{2}- x_{4} \, \mathbf{a}_{3}$ | = | $- a x_{4} \,\mathbf{\hat{x}}$ | (8g) | O II |
References
- J. M. Longo and P. M. Raccah, The structure of La$_{2}$CuO$_{4}$ and LaSrVO$_{4}$, J. Solid State Chem. 6, 526–531 (1973), doi:10.1016/S0022-4596(73)80010-6.
- M. Reehuis, C. Ulrich, K. Prokeš, A. Gozar, G. Blumberg, S. Komiya, Y. Ando, P. Pattison, and B. Keimer, Crystal structure and high-field magnetism of La$_{2}$CuO$_{4}$, Phys. Rev. B 73, 144513 (2006), doi:10.1103/PhysRevB.73.144513.
Prototype Generator
aflow --proto=AB2C4_oF28_69_a_g_cg --params=$a,b/a,c/a,x_{3},x_{4}$