Structure info
Layer group p-6m2
Layer group number 78
Structure origin original03-18
Stability
Energy above convex hull [eV/atom] 0.574
Heat of formation [eV/atom] -0.231
Dynamically stable No
Basic properties
Magnetic No
Band gap (PBE) [eV] 0.000
XYZ CIF JSON
Axis x [Å] y [Å] z [Å] Periodic
1 3.218 -0.000 0.000 Yes
2 -1.609 2.787 0.000 Yes
3 -0.000 0.000 21.280 No
Lengths [Å] 3.218 3.218 21.280
Angles [°] 90.000 90.000 120.000

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 Nb2Se2
Stoichiometry AB
Number of atoms 4
Unit cell area [Å2] 8.968
Thickness [Å] 6.305

Nb2Se2 (2NbSe-5)
Heat of formation [eV/atom] -0.23
Energy above convex hull [eV/atom] 0.57
Monolayers from C2DB
Nb7Se12 (1Nb7Se12-1) -0.90 eV/atom
Nb8Se12 (4Nb2Se3-1) -0.88 eV/atom
NbSe2 (1NbSe2-1) -0.88 eV/atom
Nb4Se6 (2Nb2Se3-1) -0.87 eV/atom
Nb7Se12 (1Nb7Se12-2) -0.85 eV/atom
NbSe2 (1NbSe2-2) -0.85 eV/atom
Nb9Se12 (3Nb3Se4-1) -0.82 eV/atom
Nb8Se12 (4Nb2Se3-2) -0.80 eV/atom
Nb9Se12 (3Nb3Se4-2) -0.75 eV/atom
Nb4Se12 (4NbSe3-1) -0.70 eV/atom
Nb2Se6 (2NbSe3-1) -0.67 eV/atom
Se2Nb4 (2SeNb2-1) -0.55 eV/atom
Nb2Se2 (2NbSe-1) -0.53 eV/atom
Nb2Se2 (2NbSe-2) -0.51 eV/atom
Nb2Se2 (2NbSe-3) -0.46 eV/atom
NbSe2 (1NbSe2-3) -0.44 eV/atom
Nb2Se2 (2NbSe-4) -0.25 eV/atom
Nb2Se2, (2NbSe-5) -0.23 eV/atom
Se2 (2Se-1) 0.21 eV/atom
Se2 (2Se-2) 0.29 eV/atom
Bulk crystals from OQMD123
Nb6Se8 -0.91 eV/atom
Nb4Se8 -0.88 eV/atom
Nb6Se18 -0.69 eV/atom
Nb8Se4 -0.55 eV/atom
Nb4Se18 -0.54 eV/atom
Nb 0.00 eV/atom
Se3 0.00 eV/atom

AB/2NbSe/5/phonon_bs.png
Minimum eigenvalue of Hessian [eV/Ų] -2.84

Cij (N/m) xx yy xy
xx 106.17 -17.94 -0.01
yy -17.79 105.88 -0.01
xy 0.00 0.00 123.67
Stiffness tensor eigenvalues
Eigenvalue 0 88.16 N/m
Eigenvalue 1 123.67 N/m
Eigenvalue 2 123.89 N/m

Key values [eV]
Band gap (PBE) 0.000
Direct band gap (PBE) 0.000
Fermi level wrt. vacuum (PBE) -5.048
DOS BZ

AB/2NbSe/5/fermi_surface.png

Atom No. Chemical symbol Charges [|e|]
0 Nb 0.58
1 Nb 0.63
2 Se -0.61
3 Se -0.61

AB/2NbSe/5/rpa-pol-x.png AB/2NbSe/5/rpa-pol-z.png
AB/2NbSe/5/rpa-pol-y.png
Properties
Interband polarizability (x) [Å] 25.115
Interband polarizability (y) [Å] 25.115
Interband polarizability (z) [Å] 0.763
Plasma frequency (x) [eV Å0.5] 5.863
Plasma frequency (y) [eV Å0.5] 5.863

Miscellaneous details
Unique ID 2NbSe-5
Number of atoms 4
Number of species 2
Formula Nb2Se2
Reduced formula NbSe
Stoichiometry AB
Unit cell area [Å2] 8.968
Original file-system folder /home/niflheim2/cmr/C2DB-ASR/tree/AB/NbSe/Nb2Se2-d3ce7385d21f
Old uid Nb2Se2-d3ce7385d21f
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] 6.305
Structure origin original03-18
Band gap (PBE) [eV] 0.000
Miscellaneous details
Direct band gap (PBE) [eV] 0.000
gap_dir_nosoc 0.000
Vacuum level [eV] 5.923
Fermi level wrt. vacuum (PBE) [eV] -5.048
minhessianeig -2.836
Dynamically stable No
Interband polarizability (x) [Å] 25.115
Interband polarizability (y) [Å] 25.115
Interband polarizability (z) [Å] 0.763
Plasma frequency (x) [eV Å0.5] 5.863
Plasma frequency (y) [eV Å0.5] 5.863
Energy [eV] -28.542
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] 0.574
Heat of formation [eV/atom] -0.231