Overview: Nb₂O₄

Structure info
Layer group	p2_1/m11
Layer group number	15
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.257
Heat of formation [eV/atom]	-2.380
Dynamically stable	No

Basic properties
Magnetic	No
Band gap (PBE) [eV]	0.000

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	3.083	-0.000	0.000	Yes
2	-0.000	5.310	0.000	Yes
3	-0.000	0.000	17.176	No

Lengths [Å]	3.083	5.310	17.176
Angles [°]	90.000	90.000	90.000

Crystal structure

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	Nb2O4
Stoichiometry	AB2
Number of atoms	6
Unit cell area [Å2]	16.372
Thickness [Å]	2.351

Stability

Convex hull

Nb2O4 (2NbO2-1)
Heat of formation [eV/atom]	-2.38
Energy above convex hull [eV/atom]	0.26

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

Bulk crystals from OQMD123
Nb2O5	-2.77 eV/atom
Nb8O16	-2.64 eV/atom
Nb3O3	-2.08 eV/atom
Nb	0.00 eV/atom
O8	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-15.29

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	131.28	45.80	0.01
yy	48.25	139.04	0.01
xy	0.00	0.00	-230.94

Stiffness tensor eigenvalues
Eigenvalue 0	-230.94 N/m
Eigenvalue 1	87.99 N/m
Eigenvalue 2	182.33 N/m

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	0.000
Direct band gap (PBE)	0.000
Fermi level wrt. vacuum (PBE)	-5.619

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Nb	2.33
1	O	-1.15
2	O	-1.15
3	Nb	2.33
4	O	-1.17
5	O	-1.17

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	5.209
Interband polarizability (y) [Å]	3.832
Interband polarizability (z) [Å]	0.228
Plasma frequency (x) [eV Å0.5]	1.130
Plasma frequency (y) [eV Å0.5]	4.744

Miscellaneous

Miscellaneous details
Unique ID	2NbO2-1
Number of atoms	6
Number of species	2
Formula	Nb2O4
Reduced formula	NbO2
Stoichiometry	AB2
Unit cell area [Å2]	16.372
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/NbO2/Nb2O4-a6b0666a1912
Old uid	Nb2O4-a6b0666a1912
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]	2.351
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]	3.520
Fermi level wrt. vacuum (PBE) [eV]	-5.619
minhessianeig	-15.292
Dynamically stable	No
Interband polarizability (x) [Å]	5.209
Interband polarizability (y) [Å]	3.832
Interband polarizability (z) [Å]	0.228
Plasma frequency (x) [eV Å0.5]	1.130
Plasma frequency (y) [eV Å0.5]	4.744
Energy [eV]	-55.428
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]	0.257
Heat of formation [eV/atom]	-2.380