Overview: Nb₂O₆

Structure info
Layer group	pmmn
Layer group number	46
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.353
Heat of formation [eV/atom]	-2.067
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	4.072	-0.000	0.000	Yes
2	0.000	2.941	0.000	Yes
3	-0.000	0.000	19.412	No

Lengths [Å]	4.072	2.941	19.412
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	46
Layer group	pmmn
Space group number (bulk in AA-stacking)	59
Space group (bulk in AA-stacking)	Pmmn
Point group	mmm
Inversion symmetry	Yes

Structure data
Formula	Nb2O6
Stoichiometry	AB3
Number of atoms	8
Unit cell area [Å2]	11.979
Thickness [Å]	4.410

Stability

Convex hull

Nb2O6 (2NbO3-1)
Heat of formation [eV/atom]	-2.07
Energy above convex hull [eV/atom]	0.35

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]

-11.83

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	257.61	64.86	0.00
yy	65.86	370.35	-0.00
xy	0.00	0.00	136.82

Stiffness tensor eigenvalues
Eigenvalue 0	136.82 N/m
Eigenvalue 1	227.67 N/m
Eigenvalue 2	400.29 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)	-6.637

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Nb	2.69
1	Nb	2.69
2	O	-1.16
3	O	-1.16
4	O	-0.77
5	O	-0.77
6	O	-0.77
7	O	-0.77

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	2.242
Interband polarizability (y) [Å]	3.398
Interband polarizability (z) [Å]	0.398
Plasma frequency (x) [eV Å0.5]	0.796
Plasma frequency (y) [eV Å0.5]	14.419

Miscellaneous

Miscellaneous details
Unique ID	2NbO3-1
Number of atoms	8
Number of species	2
Formula	Nb2O6
Reduced formula	NbO3
Stoichiometry	AB3
Unit cell area [Å2]	11.979
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB3/NbO3/Nb2O6-f741f238652c
Old uid	Nb2O6-f741f238652c
Space group (bulk in AA-stacking)	Pmmn
Space group number (bulk in AA-stacking)	59
Point group	mmm
Inversion symmetry	Yes
Layer group number	46
Layer group	pmmn
2D Bravais type	Rectangular (op)
Thickness [Å]	4.410
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]	5.090
Fermi level wrt. vacuum (PBE) [eV]	-6.637
minhessianeig	-11.828
Dynamically stable	No
Interband polarizability (x) [Å]	2.242
Interband polarizability (y) [Å]	3.398
Interband polarizability (z) [Å]	0.398
Plasma frequency (x) [eV Å0.5]	0.796
Plasma frequency (y) [eV Å0.5]	14.419
Energy [eV]	-67.931
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]	0.353
Heat of formation [eV/atom]	-2.067