| Structure info | |
|---|---|
| Layer group | p2_1/m11 |
| Layer group number | 15 |
| Structure origin | exfoliated02-21 |
| ICSD id of parent bulk structure | ICSD 418061 |
| Stability | |
|---|---|
| Energy above convex hull [eV/atom] | 0.000 |
| Heat of formation [eV/atom] | -2.093 |
| Dynamically stable | Yes |
| Basic properties | |
|---|---|
| Magnetic | No |
| Band gap (PBE) [eV] | 1.188 |
| Band gap (HSE06) [eV] | 2.295 |
| Symmetries | |
|---|---|
| 2D Bravais type | Rectangular (op) |
| Layer group number | 15 |
| Layer group | p2_1/m11 |
| Space group number (bulk in AA-stacking) | 11 |
| Space group (bulk in AA-stacking) | P2_1/m |
| Point group | 2/m |
| Inversion symmetry | Yes |
| Structure data | |
|---|---|
| Formula | Nb2I2O4 |
| Stoichiometry | ABC2 |
| Number of atoms | 8 |
| Unit cell area [Å2] | 15.063 |
| Thickness [Å] | 7.370 |
| I2Nb2O4 (2INbO2-1) | |
|---|---|
| Heat of formation [eV/atom] | -2.09 |
| Energy above convex hull [eV/atom] | 0.00 |
| 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 |
| Nb4IO7 (1INb4O7-1) | -2.19 eV/atom |
| Nb2I2O4, (2INbO2-1) | -2.09 eV/atom |
| Nb2O6 (2NbO3-1) | -2.07 eV/atom |
| Nb4O12 (4NbO3-1) | -1.83 eV/atom |
| Nb3I2O4 (1I2Nb3O4-1) | -1.75 eV/atom |
| Nb2O2 (2NbO-1) | -1.53 eV/atom |
| Nb2I2O2 (2INbO-1) | -1.39 eV/atom |
| Nb2I4O2 (2NbOI2-1) | -1.36 eV/atom |
| Nb2O2 (2NbO-2) | -1.30 eV/atom |
| Nb2O2 (2NbO-3) | -1.02 eV/atom |
| Nb2I2O (1OI2Nb2-1) | -0.77 eV/atom |
| Nb3I7O (1ONb3I7-1) | -0.74 eV/atom |
| Nb3I8 (1Nb3I8-1) | -0.54 eV/atom |
| Nb2I6 (2NbI3-1) | -0.42 eV/atom |
| Nb2I4 (2NbI2-1) | -0.37 eV/atom |
| Nb2I6 (2NbI3-2) | -0.36 eV/atom |
| NbI2 (1NbI2-1) | -0.18 eV/atom |
| NbI2 (1NbI2-2) | -0.12 eV/atom |
| NbI2 (1NbI2-3) | 0.13 eV/atom |
| Nb2I2 (2INb-1) | 0.14 eV/atom |
| Nb2I2 (2INb-2) | 0.15 eV/atom |
| Minimum eigenvalue of Hessian [eV/Ų] | -0.00 |
| DVB [eV] | xx | yy | xy |
| Γ | -0.97 | -5.93 | 0.00 |
| X | -2.34 | -5.40 | 0.00 |
| S | -1.83 | 2.54 | 0.00 |
| Y | -10.20 | -2.35 | -0.00 |
| kVBM | -2.22 | -5.83 | 0.00 |
| xx | yy | xy | |
| Band gap [eV] | -5.80 | 16.13 | -0.00 |
| DCB [eV] | xx | yy | xy |
| Γ | -8.02 | 10.30 | 0.00 |
| X | -1.67 | 6.33 | 0.00 |
| S | -8.29 | 0.81 | 0.00 |
| Y | -2.11 | 0.85 | -0.00 |
| kCBM | -8.02 | 10.30 | 0.00 |
| Cij (N/m) | xx | yy | xy |
| xx | 168.99 | 21.90 | -0.00 |
| yy | 16.68 | 113.75 | -0.00 |
| xy | 0.00 | 0.00 | 65.59 |
| Stiffness tensor eigenvalues | |
| Eigenvalue 0 | 65.59 N/m |
| Eigenvalue 1 | 107.78 N/m |
| Eigenvalue 2 | 174.96 N/m |
| Key values [eV] | |
|---|---|
| Band gap (PBE) | 1.188 |
| Direct band gap (PBE) | 1.273 |
| Valence band maximum wrt. vacuum (PBE) | -5.678 |
| Conduction band minimum wrt. vacuum (PBE) | -4.490 |
| Key values [eV] | |
|---|---|
| Band gap (HSE06) | 2.295 |
| Direct band gap (HSE06) | 2.484 |
| Valence band maximum wrt. vacuum (HSE06) | -6.242 |
| Conduction band minimum wrt. vacuum (HSE06) | -3.947 |
| Property (VBM) | Value |
|---|---|
| Min eff. mass | 0.55 m0 |
| Max eff. mass | 1.60 m0 |
| DOS eff. mass | 0.93 m0 |
| Crystal coordinates | [0.442, 0.000] |
| Warping parameter | -0.008 |
| Barrier height | > 18.4 meV |
| Distance to barrier | > 0.017 Å-1 |
| Property (CBM) | Value |
|---|---|
| Min eff. mass | 0.60 m0 |
| Max eff. mass | 1.56 m0 |
| DOS eff. mass | 0.97 m0 |
| Crystal coordinates | [0.057, 0.000] |
| Warping parameter | 0.000 |
| Barrier height | > 6.7 meV |
| Distance to barrier | > 0.0165 Å-1 |
| ZNbij | ux | uy | uz |
| Px | 6.56 | 0.00 | -0.00 |
| Py | 0.00 | 6.23 | 0.19 |
| Pz | -0.00 | 0.11 | 0.94 |
| ZIij | ux | uy | uz |
| Px | -1.36 | 0.00 | -0.00 |
| Py | -0.00 | -0.12 | 0.08 |
| Pz | -0.00 | 0.01 | -0.20 |
| ZNbij | ux | uy | uz |
| Px | 6.56 | -0.00 | -0.00 |
| Py | -0.00 | 6.23 | 0.19 |
| Pz | -0.00 | 0.11 | 0.94 |
| ZIij | ux | uy | uz |
| Px | -1.36 | -0.00 | -0.00 |
| Py | 0.00 | -0.12 | 0.08 |
| Pz | -0.00 | 0.01 | -0.20 |
| ZOij | ux | uy | uz |
| Px | -1.31 | -0.00 | 0.00 |
| Py | -0.00 | -5.24 | -0.08 |
| Pz | -0.00 | -0.04 | -0.19 |
| ZOij | ux | uy | uz |
| Px | -3.90 | -0.00 | -0.00 |
| Py | 0.00 | -0.87 | -0.19 |
| Pz | 0.00 | -0.09 | -0.55 |
| ZOij | ux | uy | uz |
| Px | -1.31 | -0.00 | 0.00 |
| Py | 0.00 | -5.24 | -0.08 |
| Pz | -0.00 | -0.04 | -0.19 |
| ZOij | ux | uy | uz |
| Px | -3.90 | -0.00 | -0.00 |
| Py | 0.00 | -0.87 | -0.19 |
| Pz | -0.00 | -0.09 | -0.55 |
| Atom No. | Chemical symbol | Charges [|e|] |
|---|---|---|
| 0 | Nb | 2.53 |
| 1 | O | -1.02 |
| 2 | I | -0.37 |
| 3 | O | -1.14 |
| 4 | Nb | 2.53 |
| 5 | O | -1.02 |
| 6 | I | -0.37 |
| 7 | O | -1.14 |
| Properties | |
|---|---|
| Interband polarizability (x) [Å] | 4.715 |
| Interband polarizability (y) [Å] | 3.346 |
| Interband polarizability (z) [Å] | 0.658 |
| Static polarizability [Å] | |
|---|---|
| Phonons only (x) | 8.83 |
| Phonons only (y) | 3.53 |
| Phonons only (z) | 0.06 |
| Total (phonons + electrons) (x) | 13.54 |
| Total (phonons + electrons) (y) | 6.87 |
| Total (phonons + electrons) (z) | 0.72 |
| Miscellaneous details | |
|---|---|
| Unique ID | 2INbO2-1 |
| Number of atoms | 8 |
| Number of species | 3 |
| Formula | Nb2I2O4 |
| Reduced formula | NbIO2 |
| Stoichiometry | ABC2 |
| Unit cell area [Å2] | 15.063 |
| Original file-system folder | /home/niflheim2/cmr/C2DB-ASR/ICSD-COD/3el/Nb4I4O8 |
| Old uid | I2Nb2O4-8b99d87752f2 |
| Space group (bulk in AA-stacking) | P2_1/m |
| Space group number (bulk in AA-stacking) | 11 |
| Point group | 2/m |
| Inversion symmetry | Yes |
| Layer group number | 15 |
| Layer group | p2_1/m11 |
| 2D Bravais type | Rectangular (op) |
| Thickness [Å] | 7.370 |
| Structure origin | exfoliated02-21 |
| Band gap (PBE) [eV] | 1.188 |
| Direct band gap (PBE) [eV] | 1.273 |
| gap_dir_nosoc | 1.327 |
| Vacuum level [eV] | 2.930 |
| Fermi level wrt. vacuum (PBE) [eV] | -5.084 |
| Valence band maximum wrt. vacuum (PBE) [eV] | -5.678 |
| Conduction band minimum wrt. vacuum (PBE) [eV] | -4.490 |
| Miscellaneous details | |
|---|---|
| minhessianeig | -0.000 |
| Dynamically stable | Yes |
| Band gap (HSE06) [eV] | 2.295 |
| Direct band gap (HSE06) [eV] | 2.484 |
| Fermi level wrt. vacuum (HSE) [eV] | -5.094 |
| Valence band maximum wrt. vacuum (HSE06) [eV] | -6.242 |
| Conduction band minimum wrt. vacuum (HSE06) [eV] | -3.947 |
| Interband polarizability (x) [Å] | 4.715 |
| Interband polarizability (y) [Å] | 3.346 |
| Interband polarizability (z) [Å] | 0.658 |
| Static polarizability (phonons) (x) [Å] | 8.826 |
| Static polarizability (phonons + electrons) (x) [Å] | 13.541 |
| Static polarizability (phonons) (y) [Å] | 3.528 |
| Static polarizability (phonons + electrons) (y) [Å] | 6.874 |
| Static polarizability (phonons) (z) [Å] | 0.064 |
| Static polarizability (phonons + electrons) (z) [Å] | 0.722 |
| Energy [eV] | -60.851 |
| ICSD id of parent bulk structure | ICSD 418061 |
| 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] | -2.093 |
