| Structure info | |
|---|---|
| Layer group | p-6m2 |
| Layer group number | 78 |
| Structure origin | original03-18 |
| Stability | |
|---|---|
| Energy above convex hull [eV/atom] | 0.000 |
| Heat of formation [eV/atom] | -0.717 |
| Dynamically stable | Yes |
| Basic properties | |
|---|---|
| Magnetic | No |
| Band gap (PBE) [eV] | 1.997 |
| Band gap (HSE06) [eV] | 2.721 |
| Band gap (G₀W₀) [eV] | 3.537 |
| Symmetries | |
|---|---|
| 2D Bravais type | Hexagonal (hp) |
| Layer group number | 78 |
| Layer group | p-6m2 |
| Space group number (bulk in AA-stacking) | 187 |
| Space group (bulk in AA-stacking) | P-6m2 |
| Point group | -6m2 |
| Inversion symmetry | No |
| Structure data | |
|---|---|
| Formula | Se2Al2 |
| Stoichiometry | AB |
| Number of atoms | 4 |
| Unit cell area [Å2] | 12.359 |
| Thickness [Å] | 4.923 |
| Al2Se2 (2AlSe-1) | |
|---|---|
| Heat of formation [eV/atom] | -0.72 |
| Energy above convex hull [eV/atom] | 0.00 |
| Monolayers from C2DB | |
|---|---|
| Al8Se12 (4Al2Se3-1) | -0.86 eV/atom |
| Al4Se6 (2Al2Se3-1) | -0.84 eV/atom |
| Al4Se6 (2Al2Se3-2) | -0.83 eV/atom |
| Al4Se6 (2Al2Se3-3) | -0.81 eV/atom |
| Al2Se3 (1Al2Se3-1) | -0.79 eV/atom |
| Al6Se9 (3Al2Se3-1) | -0.77 eV/atom |
| Al2Se3 (1Al2Se3-2) | -0.77 eV/atom |
| Al3Se4 (1Al3Se4-1) | -0.72 eV/atom |
| Al2Se2, (2AlSe-1) | -0.72 eV/atom |
| Al2Se2 (2AlSe-2) | -0.71 eV/atom |
| Al2Se2 (2AlSe-3) | -0.69 eV/atom |
| Al2Se5 (1Al2Se5-1) | -0.60 eV/atom |
| Al2Se4 (2AlSe2-1) | -0.55 eV/atom |
| AlSe2 (1AlSe2-1) | -0.55 eV/atom |
| Al2Se2 (2AlSe-4) | -0.36 eV/atom |
| Al2Se4 (2AlSe2-2) | -0.31 eV/atom |
| Al2Se2 (2AlSe-5) | -0.14 eV/atom |
| AlSe4 (1AlSe4-1) | -0.13 eV/atom |
| Se2 (2Se-1) | 0.21 eV/atom |
| Se2 (2Se-2) | 0.29 eV/atom |
| Minimum eigenvalue of Hessian [eV/Ų] | -0.00 |
| DVB [eV] | xx | yy | xy |
| Γ | 2.41 | 2.31 | -0.00 |
| M | -0.04 | 1.91 | -1.69 |
| K | -0.01 | -0.13 | -0.00 |
| kVBM | 2.56 | 1.83 | -0.32 |
| xx | yy | xy | |
| Band gap [eV] | -0.91 | -4.69 | 4.12 |
| DCB [eV] | xx | yy | xy |
| Γ | -9.09 | -9.07 | -0.00 |
| M | 1.65 | -2.85 | 3.80 |
| K | 2.60 | 2.47 | -0.00 |
| kCBM | 1.65 | -2.85 | 3.80 |
| Cij (N/m) | xx | yy | xy |
| xx | 71.84 | 19.36 | -0.00 |
| yy | 18.80 | 72.63 | -0.00 |
| xy | 0.00 | 0.00 | 54.56 |
| Stiffness tensor eigenvalues | |
| Eigenvalue 0 | 53.15 N/m |
| Eigenvalue 1 | 54.56 N/m |
| Eigenvalue 2 | 91.31 N/m |
| cij [e/Å] | xx | yy | xy |
| x | -0.00 | -0.00 | -0.06 |
| y | -0.04 | 0.04 | 0.00 |
| z | 0.00 | -0.00 | 0.00 |
| cijclamped [e/Å] | xx | yy | xy |
| x | -0.00 | -0.00 | -0.29 |
| y | -0.29 | 0.29 | 0.00 |
| z | 0.00 | 0.00 | 0.00 |
| Key values [eV] | |
|---|---|
| Band gap (PBE) | 1.997 |
| Direct band gap (PBE) | 2.645 |
| Valence band maximum wrt. vacuum (PBE) | -5.826 |
| Conduction band minimum wrt. vacuum (PBE) | -3.828 |
| Key values [eV] | |
|---|---|
| Band gap (HSE06) | 2.721 |
| Direct band gap (HSE06) | 3.435 |
| Valence band maximum wrt. vacuum (HSE06) | -6.313 |
| Conduction band minimum wrt. vacuum (HSE06) | -3.593 |
| Key values [eV] | |
|---|---|
| Band gap (G₀W₀) | 3.537 |
| Direct band gap (G₀W₀) | 4.206 |
| Valence band maximum wrt. vacuum (G₀W₀) | -7.032 |
| Conduction band minimum wrt. vacuum (G₀W₀) | -3.495 |
| Property (VBM) | Value |
|---|---|
| Min eff. mass | 1.87 m0 |
| Max eff. mass | 5.11 m0 |
| DOS eff. mass | 3.09 m0 |
| Crystal coordinates | [0.113, 0.113] |
| Warping parameter | -0.000 |
| Barrier height | > 12.6 meV |
| Distance to barrier | > 0.0255 Å-1 |
| Property (CBM) | Value |
|---|---|
| Min eff. mass | 0.29 m0 |
| Max eff. mass | 1.50 m0 |
| DOS eff. mass | 0.73 m0 |
| Crystal coordinates | [0.499, 0.001] |
| Warping parameter | 0.004 |
| Barrier height | > 72.8 meV |
| Distance to barrier | > 0.0255 Å-1 |
| ZAlij | ux | uy | uz |
| Px | 2.11 | -0.00 | -0.00 |
| Py | 0.00 | 2.11 | 0.00 |
| Pz | -0.00 | -0.00 | 0.27 |
| ZSeij | ux | uy | uz |
| Px | -2.11 | 0.00 | 0.00 |
| Py | -0.00 | -2.11 | -0.00 |
| Pz | -0.00 | 0.00 | -0.27 |
| ZAlij | ux | uy | uz |
| Px | 2.11 | -0.00 | 0.00 |
| Py | 0.00 | 2.11 | -0.00 |
| Pz | 0.00 | 0.00 | 0.27 |
| ZSeij | ux | uy | uz |
| Px | -2.11 | 0.00 | -0.00 |
| Py | -0.00 | -2.11 | 0.00 |
| Pz | 0.00 | -0.00 | -0.27 |
| Atom No. | Chemical symbol | Charges [|e|] |
|---|---|---|
| 0 | Al | 1.38 |
| 1 | Al | 1.43 |
| 2 | Se | -1.40 |
| 3 | Se | -1.40 |
| Properties | |
|---|---|
| Interband polarizability (x) [Å] | 3.631 |
| Interband polarizability (y) [Å] | 3.631 |
| Interband polarizability (z) [Å] | 0.517 |
| Plasma frequency (x) [eV Å0.5] | 0.000 |
| Plasma frequency (y) [eV Å0.5] | 0.000 |
| Static polarizability [Å] | |
|---|---|
| Phonons only (x) | 1.74 |
| Phonons only (y) | 1.74 |
| Phonons only (z) | 0.02 |
| Total (phonons + electrons) (x) | 5.37 |
| Total (phonons + electrons) (y) | 5.37 |
| Total (phonons + electrons) (z) | 0.54 |
| Exciton binding energy (BSE) [eV] | 1.10 |
| Element | Relations |
|---|---|
| yyy | yyy=-xxy=-yxx=-xyx |
| Others | 0=xxx=xxz=xyy=xyz=xzx=xzy=xzz=yxy=yxz=yyx=yyz=yzx= yzy=yzz=zxx=zxy=zxz=zyx=zyy=zyz=zzx=zzy=zzz |
| Element | Relations |
|---|---|
| yyy | yyy=-xyx=-yxx=-xxy |
| Others | 0=xxx=xxz=xyy=xyz=xzx=xzy=xzz=yxy=yxz=yyx=yyz=yzx= yzy=yzz=zxx=zxy=zxz=zyx=zyy=zyz=zzx=zzy=zzz |
| Mode | Frequency (1/cm) | Degeneracy |
|---|---|---|
| Mode 1 | 0. | 3 |
| Mode 2 | 59.2 | 2 |
| Mode 3 | 125.4 | 1 |
| Mode 4 | 294.6 | 4 |
| Mode 5 | 329.2 | 1 |
| Mode 6 | 458.2 | 1 |
| Miscellaneous details | |
|---|---|
| Unique ID | 2AlSe-1 |
| Number of atoms | 4 |
| Number of species | 2 |
| Formula | Se2Al2 |
| Reduced formula | SeAl |
| Stoichiometry | AB |
| Unit cell area [Å2] | 12.359 |
| Original file-system folder | /home/niflheim2/cmr/C2DB-ASR/tree/AB/AlSe/Al2Se2-129a514b51ad |
| Old uid | Al2Se2-129a514b51ad |
| Space group (bulk in AA-stacking) | P-6m2 |
| Space group number (bulk in AA-stacking) | 187 |
| Point group | -6m2 |
| Inversion symmetry | No |
| Layer group number | 78 |
| Layer group | p-6m2 |
| 2D Bravais type | Hexagonal (hp) |
| Thickness [Å] | 4.923 |
| Structure origin | original03-18 |
| Band gap (PBE) [eV] | 1.997 |
| Direct band gap (PBE) [eV] | 2.645 |
| gap_dir_nosoc | 2.651 |
| Vacuum level [eV] | 3.820 |
| Fermi level wrt. vacuum (PBE) [eV] | -4.827 |
| Valence band maximum wrt. vacuum (PBE) [eV] | -5.826 |
| Conduction band minimum wrt. vacuum (PBE) [eV] | -3.828 |
| minhessianeig | -0.000 |
| Dynamically stable | Yes |
| Band gap (HSE06) [eV] | 2.721 |
| Miscellaneous details | |
|---|---|
| Direct band gap (HSE06) [eV] | 3.435 |
| Fermi level wrt. vacuum (HSE) [eV] | -4.637 |
| Valence band maximum wrt. vacuum (HSE06) [eV] | -6.313 |
| Conduction band minimum wrt. vacuum (HSE06) [eV] | -3.593 |
| Band gap (G₀W₀) [eV] | 3.537 |
| Direct band gap (G₀W₀) [eV] | 4.206 |
| Fermi level wrt. vacuum (G₀W₀) [eV] | -5.264 |
| Valence band maximum wrt. vacuum (G₀W₀) [eV] | -7.032 |
| Conduction band minimum wrt. vacuum (G₀W₀) [eV] | -3.495 |
| E_B | 1.096 |
| Interband polarizability (x) [Å] | 3.631 |
| Interband polarizability (y) [Å] | 3.631 |
| Interband polarizability (z) [Å] | 0.517 |
| Static polarizability (phonons) (x) [Å] | 1.738 |
| Static polarizability (phonons + electrons) (x) [Å] | 5.368 |
| Static polarizability (phonons) (y) [Å] | 1.737 |
| Static polarizability (phonons + electrons) (y) [Å] | 5.368 |
| Static polarizability (phonons) (z) [Å] | 0.021 |
| Static polarizability (phonons + electrons) (z) [Å] | 0.538 |
| Plasma frequency (x) [eV Å0.5] | 0.000 |
| Plasma frequency (y) [eV Å0.5] | 0.000 |
| Energy [eV] | -17.311 |
| Magnetic | No |
| Spin axis | z |
| Magnetic anisotropy energy, xz [meV/unit cell] | 0.000 |
| Magnetic anisotropy energy, yz [meV/unit cell] | 0.000 |
| Energy above convex hull [eV/atom] | 0.000 |
| Heat of formation [eV/atom] | -0.717 |
