| Structure info | |
|---|---|
| Layer group | p-3m1 |
| Layer group number | 72 |
| Structure origin | original03-18 |
| Stability | |
|---|---|
| Energy above convex hull [eV/atom] | 0.259 |
| Heat of formation [eV/atom] | -0.872 |
| Dynamically stable | Yes |
| Basic properties | |
|---|---|
| Magnetic | No |
| Topology | Z2=1 |
| Band gap (PBE) [eV] | 0.041 |
| Band gap (HSE06) [eV] | 0.026 |
| Symmetries | |
|---|---|
| 2D Bravais type | Hexagonal (hp) |
| Layer group number | 72 |
| Layer group | p-3m1 |
| Space group number (bulk in AA-stacking) | 164 |
| Space group (bulk in AA-stacking) | P-3m1 |
| Point group | -3m |
| Inversion symmetry | Yes |
| Structure data | |
|---|---|
| Formula | Ti2Se2 |
| Stoichiometry | AB |
| Number of atoms | 4 |
| Unit cell area [Å2] | 14.154 |
| Thickness [Å] | 3.559 |
| Se2Ti2 (2SeTi-1) | |
|---|---|
| Heat of formation [eV/atom] | -0.87 |
| Energy above convex hull [eV/atom] | 0.26 |
| Monolayers from C2DB | |
|---|---|
| Ti4Se8 (4TiSe2-1) | -1.13 eV/atom |
| Ti2Se3 (1Ti2Se3-1) | -1.12 eV/atom |
| TiSe2 (1TiSe2-1) | -1.12 eV/atom |
| TiSe2 (1TiSe2-2) | -1.00 eV/atom |
| Ti2Se2, (2SeTi-1) | -0.87 eV/atom |
| TiSe2 (1TiSe2-3) | -0.86 eV/atom |
| Ti2Se2 (2SeTi-2) | -0.83 eV/atom |
| Ti2Se6 (2TiSe3-1) | -0.83 eV/atom |
| Ti2Se2 (2SeTi-3) | -0.78 eV/atom |
| Ti2Se2 (2SeTi-4) | -0.56 eV/atom |
| Ti2Se2 (2SeTi-5) | -0.55 eV/atom |
| Se2 (2Se-1) | 0.21 eV/atom |
| Se2 (2Se-2) | 0.29 eV/atom |
| Minimum eigenvalue of Hessian [eV/Ų] | -0.00 |
| Cij (N/m) | xx | yy | xy |
| xx | 50.23 | 41.85 | 0.01 |
| yy | 42.61 | 50.33 | 0.02 |
| xy | -0.01 | -0.02 | 8.96 |
| Stiffness tensor eigenvalues | |
| Eigenvalue 0 | 8.05 N/m |
| Eigenvalue 1 | 8.96 N/m |
| Eigenvalue 2 | 92.51 N/m |
| Key values [eV] | |
|---|---|
| Band gap (PBE) | 0.041 |
| Direct band gap (PBE) | 0.041 |
| Valence band maximum wrt. vacuum (PBE) | -4.204 |
| Conduction band minimum wrt. vacuum (PBE) | -4.163 |
| Key values [eV] | |
|---|---|
| Band gap (HSE06) | 0.026 |
| Direct band gap (HSE06) | 0.026 |
| Valence band maximum wrt. vacuum (HSE06) | -3.788 |
| Conduction band minimum wrt. vacuum (HSE06) | -3.762 |
| Property (VBM) | Value |
|---|---|
| Min eff. mass | 0.03 m0 |
| Max eff. mass | 0.07 m0 |
| DOS eff. mass | 0.05 m0 |
| Crystal coordinates | [0.213, 0.213] |
| Warping parameter | -0.000 |
| Barrier height | > 76.3 meV |
| Distance to barrier | > 0.0179 Å-1 |
| Property (CBM) | Value |
|---|---|
| Min eff. mass | 0.03 m0 |
| Max eff. mass | 0.08 m0 |
| DOS eff. mass | 0.04 m0 |
| Crystal coordinates | [0.213, 0.213] |
| Warping parameter | 0.000 |
| Barrier height | > 77.6 meV |
| Distance to barrier | > 0.018 Å-1 |
| ZSeij | ux | uy | uz |
| Px | 73.92 | 36.89 | -102.69 |
| Py | 0.03 | 63.75 | 58.93 |
| Pz | 0.00 | -0.00 | -0.16 |
| ZTiij | ux | uy | uz |
| Px | -73.64 | -37.12 | 102.82 |
| Py | -0.04 | -62.93 | -59.03 |
| Pz | -0.00 | 0.00 | 0.16 |
| ZSeij | ux | uy | uz |
| Px | 73.91 | 36.89 | -102.70 |
| Py | 0.03 | 63.75 | 58.93 |
| Pz | 0.00 | -0.00 | -0.16 |
| ZTiij | ux | uy | uz |
| Px | -73.67 | -37.12 | 102.82 |
| Py | -0.04 | -62.96 | -59.03 |
| Pz | -0.00 | 0.00 | 0.16 |
| Atom No. | Chemical symbol | Charges [|e|] |
|---|---|---|
| 0 | Se | -1.14 |
| 1 | Se | -1.14 |
| 2 | Ti | 1.14 |
| 3 | Ti | 1.14 |
| Properties | |
|---|---|
| Interband polarizability (x) [Å] | 128.615 |
| Interband polarizability (y) [Å] | 131.200 |
| Interband polarizability (z) [Å] | 0.404 |
| Plasma frequency (x) [eV Å0.5] | 0.000 |
| Plasma frequency (y) [eV Å0.5] | 0.000 |
| Static polarizability [Å] | |
|---|---|
| Phonons only (x) | 4591.79 |
| Phonons only (y) | 2000.99 |
| Phonons only (z) | 0.01 |
| Total (phonons + electrons) (x) | 4720.40 |
| Total (phonons + electrons) (y) | 2132.19 |
| Total (phonons + electrons) (z) | 0.41 |
| Mode | Frequency (1/cm) | Degeneracy |
|---|---|---|
| Mode 1 | 0. | 3 |
| Mode 2 | 68.4 | 2 |
| Mode 3 | 167.7 | 1 |
| Mode 4 | 263.2 | 2 |
| Mode 5 | 277.9 | 1 |
| Mode 6 | 311.7 | 2 |
| Mode 7 | 329.3 | 1 |
| Miscellaneous details | |
|---|---|
| Unique ID | 2SeTi-1 |
| Number of atoms | 4 |
| Number of species | 2 |
| Formula | Ti2Se2 |
| Reduced formula | TiSe |
| Stoichiometry | AB |
| Unit cell area [Å2] | 14.154 |
| Original file-system folder | /home/niflheim2/cmr/C2DB-ASR/tree/AB/SeTi/Se2Ti2-f346fce11db3 |
| Old uid | Se2Ti2-f346fce11db3 |
| Space group (bulk in AA-stacking) | P-3m1 |
| Space group number (bulk in AA-stacking) | 164 |
| Point group | -3m |
| Inversion symmetry | Yes |
| Layer group number | 72 |
| Layer group | p-3m1 |
| 2D Bravais type | Hexagonal (hp) |
| Thickness [Å] | 3.559 |
| Structure origin | original03-18 |
| Band gap (PBE) [eV] | 0.041 |
| Direct band gap (PBE) [eV] | 0.041 |
| gap_dir_nosoc | 0.000 |
| Vacuum level [eV] | 3.616 |
| Fermi level wrt. vacuum (PBE) [eV] | -4.183 |
| Valence band maximum wrt. vacuum (PBE) [eV] | -4.204 |
| Conduction band minimum wrt. vacuum (PBE) [eV] | -4.163 |
| minhessianeig | -0.000 |
| Miscellaneous details | |
|---|---|
| Dynamically stable | Yes |
| Band gap (HSE06) [eV] | 0.026 |
| Direct band gap (HSE06) [eV] | 0.026 |
| Fermi level wrt. vacuum (HSE) [eV] | -3.775 |
| Valence band maximum wrt. vacuum (HSE06) [eV] | -3.788 |
| Conduction band minimum wrt. vacuum (HSE06) [eV] | -3.762 |
| Interband polarizability (x) [Å] | 128.615 |
| Interband polarizability (y) [Å] | 131.200 |
| Interband polarizability (z) [Å] | 0.404 |
| Static polarizability (phonons) (x) [Å] | 4591.785 |
| Static polarizability (phonons + electrons) (x) [Å] | 4720.400 |
| Static polarizability (phonons) (y) [Å] | 2000.986 |
| Static polarizability (phonons + electrons) (y) [Å] | 2132.186 |
| Static polarizability (phonons) (z) [Å] | 0.007 |
| Static polarizability (phonons + electrons) (z) [Å] | 0.410 |
| Plasma frequency (x) [eV Å0.5] | 0.000 |
| Plasma frequency (y) [eV Å0.5] | 0.000 |
| Energy [eV] | -23.835 |
| Magnetic | No |
| Spin axis | z |
| Magnetic anisotropy energy, xz [meV/unit cell] | 0.000 |
| Magnetic anisotropy energy, yz [meV/unit cell] | 0.000 |
| Topology | Z2=1 |
| Energy above convex hull [eV/atom] | 0.259 |
| Heat of formation [eV/atom] | -0.872 |
