Overview: BaBr₂

Structure info
Layer group	p-3m1
Layer group number	72
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.056
Heat of formation [eV/atom]	-2.210
Dynamically stable	Yes

Basic properties
Magnetic	No
Out-of-plane dipole [e Å/unit cell]	-0.000
Band gap (PBE) [eV]	4.902
Band gap (HSE) [eV]	6.031

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	4.963	0.000	0.000	Yes
2	-2.482	4.298	0.000	Yes
3	0.000	0.000	18.114	No

Lengths [Å]	4.963	4.963	18.114
Angles [°]	90.000	90.000	120.000

Crystal structure

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	BaBr2
Stoichiometry	AB2
Number of atoms	3
Unit cell area [Å2]	21.333
Thickness [Å]	3.114

Stability

Convex hull

BaBr2 (1BaBr2-1)
Heat of formation [eV/atom]	-2.21
Energy above convex hull [eV/atom]	0.06

Monolayers from C2DB
BaBr2, (1BaBr2-1)	-2.21 eV/atom
Ba2Br4 (2BaBr2-1)	-2.19 eV/atom
BaBr2 (1BaBr2-2)	-2.10 eV/atom
BaBr2 (1BaBr2-3)	-2.02 eV/atom
Ba2Br2 (2BaBr-1)	-1.31 eV/atom

Bulk crystals from OQMD123
Ba4Br8	-2.27 eV/atom
Ba	0.00 eV/atom
Br4	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Deformation potentials

DVB [eV]	xx	yy	xy
Γ	2.62	2.65	0.05
M	2.22	2.92	-0.52
K	2.97	3.03	0.05
kVBM	2.66	2.71	0.01

	xx	yy	xy
Band gap [eV]	-2.57	-2.54	0.05

DCB [eV]	xx	yy	xy
Γ	0.09	0.17	0.06
M	3.70	4.80	-0.74
K	-0.61	-0.57	0.03
kCBM	0.09	0.17	0.06

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	15.48	3.53	-0.29
yy	3.74	15.04	-0.32
xy	0.00	0.00	11.55

Stiffness tensor eigenvalues
Eigenvalue 0	11.55 N/m
Eigenvalue 1	11.62 N/m
Eigenvalue 2	18.90 N/m

Electronic bands

Band structure and DOS (PBE)

Properties [eV]
Band gap	4.902
Direct band gap	4.920
VBM wrt. vacuum	-7.236
CBM wrt. vacuum	-2.334
Vacuum level shift	-0.000

Band structure (HSE06@PBE)

Properties [eV]
Band gap	6.031
Direct band gap	6.050
VBM wrt. vacuum	-8.098
CBM wrt. vacuum	-2.067

Effective masses

Property (VBM)	Value
Min eff. mass	4.23 m0
Max eff. mass	133.04 m0
DOS eff. mass	23.71 m0
Crystal coordinates	[0.120, 0.117]
Warping parameter	-0.001
Barrier height	> 0.2 meV
Distance to barrier	> 0.0147 Å-1

Property (CBM)	Value
Min eff. mass	0.45 m0
Max eff. mass	0.45 m0
DOS eff. mass	0.45 m0
Crystal coordinates	[0.000, -0.000]
Warping parameter	0.000
Barrier height	> 69.3 meV
Distance to barrier	> 0.0146 Å-1

Electronic properties

Born charges

ZBaij	ux	uy	uz
Px	2.77	0.00	-0.00
Py	0.00	2.77	0.00
Pz	-0.00	-0.00	0.86

ZBrij	ux	uy	uz
Px	-1.38	-0.00	0.00
Py	-0.00	-1.38	-0.00
Pz	0.00	0.00	-0.43

ZBrij	ux	uy	uz
Px	-1.38	-0.00	0.00
Py	-0.00	-1.38	-0.00
Pz	0.00	0.00	-0.43

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Ba	1.55
1	Br	-0.77
2	Br	-0.77

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	0.874
Interband polarizability (y) [Å]	0.874
Interband polarizability (z) [Å]	0.293
Plasma frequency (x) [eV Å0.5]	0.000
Plasma frequency (y) [eV Å0.5]	0.000

Infrared polarizability

Static polarizability [Å]
Phonons only (x)	1.93
Phonons only (y)	1.93
Phonons only (z)	0.12
Total (phonons + electrons) (x)	2.80
Total (phonons + electrons) (y)	2.80
Total (phonons + electrons) (z)	0.41

Optical absorption (BSE and RPA)

Exciton binding energy (BSE) [eV]

1.85

Raman spectrum

Mode	Frequency (1/cm)	Degeneracy
Mode 1	0.	3
Mode 2	90.	2
Mode 3	92.	1
Mode 4	106.9	2
Mode 5	129.7	1

Miscellaneous

Miscellaneous details
Unique ID	1BaBr2-1
Number of atoms	3
Number of species	2
Formula	BaBr2
Reduced formula	BaBr2
Stoichiometry	AB2
Unit cell area [Å2]	21.333
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/BaBr2/BaBr2-74dc20d8f1ff
Old uid	BaBr2-74dc20d8f1ff
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]	3.114
Structure origin	original03-18
Band gap [eV]	4.902
Direct band gap [eV]	4.920
gap_dir_nosoc	5.067
Vacuum level [eV]	2.660
Fermi level wrt. vacuum [eV]	-4.785
VBM wrt. vacuum [eV]	-7.236
CBM wrt. vacuum [eV]	-2.334
Vacuum level shift [eV]	-0.000
Out-of-plane dipole [e Å/unit cell]	-0.000

Miscellaneous details
minhessianeig	-0.000
Dynamically stable	Yes
Band gap [eV]	6.031
Direct band gap [eV]	6.050
Fermi level wrt. vacuum [eV]	-3.167
VBM wrt. vacuum [eV]	-8.098
CBM wrt. vacuum [eV]	-2.067
E_B	1.850
Interband polarizability (x) [Å]	0.874
Interband polarizability (y) [Å]	0.874
Interband polarizability (z) [Å]	0.293
Static polarizability (phonons) (x) [Å]	1.928
Static polarizability (phonons + electrons) (x) [Å]	2.802
Static polarizability (phonons) (y) [Å]	1.930
Static polarizability (phonons + electrons) (y) [Å]	2.805
Static polarizability (phonons) (z) [Å]	0.121
Static polarizability (phonons + electrons) (z) [Å]	0.414
Plasma frequency (x) [eV Å0.5]	0.000
Plasma frequency (y) [eV Å0.5]	0.000
Energy [eV]	-11.627
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]	0.056
Heat of formation [eV/atom]	-2.210