| Structure info | |
|---|---|
| Layer group | c2/m11 |
| Layer group number | 18 |
| Structure origin | original03-18 |
| Stability | |
|---|---|
| Energy above convex hull [eV/atom] | 0.212 |
| Heat of formation [eV/atom] | -2.424 |
| Dynamically stable | Yes |
| Basic properties | |
|---|---|
| Magnetic | No |
| Topology | Trivial |
| Band gap (PBE) [eV] | 0.459 |
| Band gap (HSE06) [eV] | 1.454 |
| Symmetries | |
|---|---|
| 2D Bravais type | Centered rectangular (oc) |
| Layer group number | 18 |
| Layer group | c2/m11 |
| Space group number (bulk in AA-stacking) | 12 |
| Space group (bulk in AA-stacking) | C2/m |
| Point group | 2/m |
| Inversion symmetry | Yes |
| Structure data | |
|---|---|
| Formula | Nb4O8 |
| Stoichiometry | AB2 |
| Number of atoms | 12 |
| Unit cell area [Å2] | 32.866 |
| Thickness [Å] | 2.339 |
| Nb4O8 (4NbO2-1) | |
|---|---|
| Heat of formation [eV/atom] | -2.42 |
| Energy above convex hull [eV/atom] | 0.21 |
| Monolayers from C2DB | |
|---|---|
| Nb4O8, (4NbO2-1) | -2.42 eV/atom |
| Nb2O4 (2NbO2-1) | -2.38 eV/atom |
| NbO2 (1NbO2-1) | -2.37 eV/atom |
| NbO2 (1NbO2-2) | -2.35 eV/atom |
| NbO2 (1NbO2-3) | -2.20 eV/atom |
| Nb2O6 (2NbO3-1) | -2.07 eV/atom |
| Nb4O12 (4NbO3-1) | -1.83 eV/atom |
| Nb2O2 (2NbO-1) | -1.53 eV/atom |
| Nb2O2 (2NbO-2) | -1.30 eV/atom |
| Nb2O2 (2NbO-3) | -1.02 eV/atom |
| Minimum eigenvalue of Hessian [eV/Ų] | -0.00 |
| DVB [eV] | xx | yy | xy |
| Γ | 3.40 | 3.15 | 0.01 |
| Y | 3.24 | 0.38 | 1.58 |
| H | 2.98 | 1.01 | 1.26 |
| C | 3.30 | 3.32 | -0.17 |
| H1 | 2.98 | 1.05 | 1.24 |
| X | 2.93 | 0.61 | 1.73 |
| kVBM | 4.15 | 3.46 | 0.36 |
| xx | yy | xy | |
| Band gap [eV] | -3.25 | -0.78 | -2.82 |
| DCB [eV] | xx | yy | xy |
| Γ | 0.90 | 2.68 | -2.46 |
| Y | 4.75 | 2.36 | -0.28 |
| H | 3.31 | 1.40 | 0.92 |
| C | 1.92 | 2.10 | -1.01 |
| H1 | 3.26 | 1.23 | 0.92 |
| X | 3.19 | 3.80 | 0.61 |
| kCBM | 0.90 | 2.68 | -2.46 |
| Cij (N/m) | xx | yy | xy |
| xx | 151.27 | 38.12 | 2.64 |
| yy | 36.79 | 144.54 | 4.35 |
| xy | 1.61 | 4.94 | 109.30 |
| Stiffness tensor eigenvalues | |
| Eigenvalue 0 | 107.63 N/m |
| Eigenvalue 1 | 111.69 N/m |
| Eigenvalue 2 | 185.79 N/m |
| Key values [eV] | |
|---|---|
| Band gap (PBE) | 0.459 |
| Direct band gap (PBE) | 0.482 |
| Valence band maximum wrt. vacuum (PBE) | -5.481 |
| Conduction band minimum wrt. vacuum (PBE) | -5.022 |
| Key values [eV] | |
|---|---|
| Band gap (HSE06) | 1.454 |
| Direct band gap (HSE06) | 1.481 |
| Valence band maximum wrt. vacuum (HSE06) | -5.805 |
| Conduction band minimum wrt. vacuum (HSE06) | -4.351 |
| Property (VBM) | Value |
|---|---|
| Min eff. mass | 1.50 m0 |
| Max eff. mass | 1.67 m0 |
| DOS eff. mass | 1.58 m0 |
| Crystal coordinates | [0.118, -0.001] |
| Warping parameter | -0.000 |
| Barrier height | > 11.7 meV |
| Distance to barrier | > 0.0117 Å-1 |
| Property (CBM) | Value |
|---|---|
| Min eff. mass | 0.93 m0 |
| Max eff. mass | 1.17 m0 |
| DOS eff. mass | 1.04 m0 |
| Crystal coordinates | [0.000, -0.000] |
| Warping parameter | 0.001 |
| Barrier height | > 18.5 meV |
| Distance to barrier | > 0.012 Å-1 |
| ZNbij | ux | uy | uz |
| Px | 10.29 | 1.67 | -0.95 |
| Py | 1.67 | 8.28 | -0.54 |
| Pz | -0.17 | -0.10 | 0.91 |
| ZNbij | ux | uy | uz |
| Px | 3.20 | -0.21 | 0.78 |
| Py | -0.21 | 3.44 | 0.46 |
| Pz | 0.05 | 0.03 | 0.70 |
| ZOij | ux | uy | uz |
| Px | -2.35 | -0.84 | -0.07 |
| Py | -0.84 | -1.34 | -0.06 |
| Pz | 0.01 | 0.01 | -0.44 |
| ZOij | ux | uy | uz |
| Px | -2.46 | -1.31 | -0.24 |
| Py | -0.32 | -4.21 | -0.12 |
| Pz | -0.05 | 0.06 | -0.39 |
| ZOij | ux | uy | uz |
| Px | -4.47 | 0.85 | -0.22 |
| Py | -0.13 | -2.15 | -0.14 |
| Pz | 0.02 | -0.08 | -0.39 |
| ZOij | ux | uy | uz |
| Px | -4.21 | -0.17 | 0.71 |
| Py | -0.18 | -4.00 | 0.41 |
| Pz | 0.14 | 0.08 | -0.39 |
| ZNbij | ux | uy | uz |
| Px | 10.28 | 1.67 | -0.95 |
| Py | 1.67 | 8.27 | -0.55 |
| Pz | -0.17 | -0.10 | 0.91 |
| ZNbij | ux | uy | uz |
| Px | 3.19 | -0.20 | 0.78 |
| Py | -0.21 | 3.44 | 0.46 |
| Pz | 0.05 | 0.03 | 0.70 |
| ZOij | ux | uy | uz |
| Px | -2.35 | -0.84 | -0.07 |
| Py | -0.84 | -1.34 | -0.05 |
| Pz | 0.01 | 0.01 | -0.44 |
| ZOij | ux | uy | uz |
| Px | -2.46 | -1.31 | -0.24 |
| Py | -0.32 | -4.21 | -0.12 |
| Pz | -0.05 | 0.06 | -0.39 |
| ZOij | ux | uy | uz |
| Px | -4.46 | 0.85 | -0.22 |
| Py | -0.13 | -2.15 | -0.14 |
| Pz | 0.02 | -0.08 | -0.39 |
| ZOij | ux | uy | uz |
| Px | -4.21 | -0.16 | 0.71 |
| Py | -0.18 | -4.00 | 0.41 |
| Pz | 0.14 | 0.08 | -0.39 |
| Atom No. | Chemical symbol | Charges [|e|] |
|---|---|---|
| 0 | Nb | 2.55 |
| 1 | Nb | 2.54 |
| 2 | Nb | 2.04 |
| 3 | Nb | 2.04 |
| 4 | O | -1.12 |
| 5 | O | -1.12 |
| 6 | O | -1.16 |
| 7 | O | -1.16 |
| 8 | O | -1.15 |
| 9 | O | -1.15 |
| 10 | O | -1.15 |
| 11 | O | -1.15 |
| Properties | |
|---|---|
| Interband polarizability (x) [Å] | 4.341 |
| Interband polarizability (y) [Å] | 3.504 |
| Interband polarizability (z) [Å] | 0.229 |
| Plasma frequency (x) [eV Å0.5] | 0.000 |
| Plasma frequency (y) [eV Å0.5] | 0.000 |
| Static polarizability [Å] | |
|---|---|
| Phonons only (x) | 18.86 |
| Phonons only (y) | 12.05 |
| Phonons only (z) | 0.05 |
| Total (phonons + electrons) (x) | 23.20 |
| Total (phonons + electrons) (y) | 15.56 |
| Total (phonons + electrons) (z) | 0.27 |
| Miscellaneous details | |
|---|---|
| Unique ID | 4NbO2-1 |
| Number of atoms | 12 |
| Number of species | 2 |
| Formula | Nb4O8 |
| Reduced formula | NbO2 |
| Stoichiometry | AB2 |
| Unit cell area [Å2] | 32.866 |
| Original file-system folder | /home/niflheim2/cmr/C2DB-ASR/tree/AB2/NbO2/Nb4O8-b3130faeb4ab |
| Old uid | Nb4O8-b3130faeb4ab |
| Space group (bulk in AA-stacking) | C2/m |
| Space group number (bulk in AA-stacking) | 12 |
| Point group | 2/m |
| Inversion symmetry | Yes |
| Layer group number | 18 |
| Layer group | c2/m11 |
| 2D Bravais type | Centered rectangular (oc) |
| Thickness [Å] | 2.339 |
| Structure origin | original03-18 |
| Band gap (PBE) [eV] | 0.459 |
| Direct band gap (PBE) [eV] | 0.482 |
| gap_dir_nosoc | 0.483 |
| Vacuum level [eV] | 3.227 |
| Fermi level wrt. vacuum (PBE) [eV] | -5.252 |
| Valence band maximum wrt. vacuum (PBE) [eV] | -5.481 |
| Conduction band minimum wrt. vacuum (PBE) [eV] | -5.022 |
| minhessianeig | -0.000 |
| Miscellaneous details | |
|---|---|
| Dynamically stable | Yes |
| Band gap (HSE06) [eV] | 1.454 |
| Direct band gap (HSE06) [eV] | 1.481 |
| Fermi level wrt. vacuum (HSE) [eV] | -5.078 |
| Valence band maximum wrt. vacuum (HSE06) [eV] | -5.805 |
| Conduction band minimum wrt. vacuum (HSE06) [eV] | -4.351 |
| Interband polarizability (x) [Å] | 4.341 |
| Interband polarizability (y) [Å] | 3.504 |
| Interband polarizability (z) [Å] | 0.229 |
| Static polarizability (phonons) (x) [Å] | 18.860 |
| Static polarizability (phonons + electrons) (x) [Å] | 23.201 |
| Static polarizability (phonons) (y) [Å] | 12.054 |
| Static polarizability (phonons + electrons) (y) [Å] | 15.557 |
| Static polarizability (phonons) (z) [Å] | 0.046 |
| Static polarizability (phonons + electrons) (z) [Å] | 0.275 |
| Plasma frequency (x) [eV Å0.5] | 0.000 |
| Plasma frequency (y) [eV Å0.5] | 0.000 |
| Energy [eV] | -111.390 |
| Magnetic | No |
| Spin axis | z |
| Magnetic anisotropy energy, xz [meV/unit cell] | 0.000 |
| Magnetic anisotropy energy, yz [meV/unit cell] | 0.000 |
| Topology | Trivial |
| Energy above convex hull [eV/atom] | 0.212 |
| Heat of formation [eV/atom] | -2.424 |
