Overview: Ag₄Br₄

Structure info
Layer group	p2_12_12
Layer group number	21
Structure origin	Wang23

Stability
Energy above convex hull [eV/atom]	0.005
Heat of formation [eV/atom]	-0.342
Dynamically stable	Yes

Basic properties
Magnetic	No
Band gap (PBE) [eV]	2.330
Band gap (HSE06) [eV]	3.583

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	7.112	-0.000	0.000	Yes
2	-0.000	5.359	0.000	Yes
3	0.000	0.000	18.370	No

Lengths [Å]	7.112	5.359	18.370
Angles [°]	90.000	90.000	90.001

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	21
Layer group	p2_12_12
Space group number (bulk in AA-stacking)	18
Space group (bulk in AA-stacking)	P2_12_12
Point group	222
Inversion symmetry	No

Structure data
Formula	Ag4Br4
Stoichiometry	AB
Number of atoms	8
Unit cell area [Å2]	38.113
Thickness [Å]	3.275

Stability

Convex hull

Ag4Br4 (4AgBr-2)
Heat of formation [eV/atom]	-0.34
Energy above convex hull [eV/atom]	0.01

Monolayers from C2DB
Ag4Br4 (4AgBr-1)	-0.35 eV/atom
Ag4Br4, (4AgBr-2)	-0.34 eV/atom
Ag6Br6 (6AgBr-1)	-0.34 eV/atom
Ag2Br2 (2AgBr-1)	-0.34 eV/atom
Ag2Br2 (2AgBr-2)	-0.34 eV/atom
Ag6Br6 (6AgBr-2)	-0.34 eV/atom
Ag6Br6 (6AgBr-3)	-0.33 eV/atom
Ag2Br2 (2AgBr-3)	-0.33 eV/atom
Ag5Br5 (5AgBr-1)	-0.33 eV/atom
Ag6Br6 (6AgBr-4)	-0.32 eV/atom
Ag8Br8 (8AgBr-1)	-0.32 eV/atom
Ag12Br12 (12AgBr-1)	-0.32 eV/atom
Ag3Br3 (3AgBr-1)	-0.32 eV/atom
Ag2Br2 (2AgBr-4)	-0.31 eV/atom
Ag3Br3 (3AgBr-2)	-0.31 eV/atom
Ag3Br3 (3AgBr-3)	-0.31 eV/atom
Ag2Br2 (2AgBr-5)	-0.30 eV/atom
Ag3Br3 (3AgBr-4)	-0.30 eV/atom
Ag8Br8 (8AgBr-2)	-0.30 eV/atom
Ag8Br8 (8AgBr-3)	-0.30 eV/atom
Ag6Br6 (6AgBr-5)	-0.30 eV/atom
AgBr (1AgBr-1)	-0.30 eV/atom
Ag2Br2 (2AgBr-6)	-0.29 eV/atom
Ag2Br4 (2AgBr2-1)	-0.24 eV/atom
Ag4Br8 (4AgBr2-1)	-0.24 eV/atom
Ag6Br12 (6AgBr2-1)	-0.23 eV/atom
Ag2Br4 (2AgBr2-2)	-0.20 eV/atom
AgBr2 (1AgBr2-1)	-0.19 eV/atom
Ag2Br6 (2AgBr3-1)	-0.19 eV/atom
Ag2Br6 (2AgBr3-2)	-0.19 eV/atom
Ag4Br8 (4AgBr2-2)	-0.19 eV/atom
Ag2Br6 (2AgBr3-3)	-0.18 eV/atom
Ag4Br12 (4AgBr3-1)	-0.16 eV/atom
AgBr3 (1AgBr3-1)	-0.16 eV/atom
Ag2Br6 (2AgBr3-4)	-0.15 eV/atom
AgBr2 (1AgBr2-2)	-0.13 eV/atom
AgBr2 (1AgBr2-3)	-0.09 eV/atom
Ag2Br6 (2AgBr3-5)	-0.06 eV/atom
Ag2Br6 (2AgBr3-6)	0.01 eV/atom
Ag2 (2Ag-1)	0.31 eV/atom

Bulk crystals from OQMD123
AgBr	-0.32 eV/atom
Ag4Br6	-0.28 eV/atom
Ag4	0.00 eV/atom
Br4	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	8.66	2.52	-0.01
yy	3.12	3.11	-0.01
xy	-0.00	0.00	11.06

Stiffness tensor eigenvalues
Eigenvalue 0	1.94 N/m
Eigenvalue 1	9.83 N/m
Eigenvalue 2	11.06 N/m

Piezoelectric tensor

cij [e/Å]	xx	yy	xy
x	-0.00	-0.00	-0.00
y	0.00	0.00	0.00
z	0.00	0.00	-0.02

cijclamped [e/Å]	xx	yy	xy
x	-0.00	-0.00	-0.00
y	-0.00	-0.00	0.00
z	0.00	0.00	0.01

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	2.330
Direct band gap (PBE)	2.400
Valence band maximum wrt. vacuum (PBE)	-6.366
Conduction band minimum wrt. vacuum (PBE)	-4.036

Electronic band structure (HSE06@PBE)

Key values [eV]
Band gap (HSE06)	3.583
Direct band gap (HSE06)	3.671
Valence band maximum wrt. vacuum (HSE06)	-7.405
Conduction band minimum wrt. vacuum (HSE06)	-3.822

Electronic properties

Born charges

ZAgij	ux	uy	uz
Px	1.50	0.19	-0.00
Py	-0.14	1.04	-0.00
Pz	-0.00	-0.00	0.35

ZAgij	ux	uy	uz
Px	0.97	0.39	0.00
Py	0.24	0.76	-0.00
Pz	0.00	-0.00	0.21

ZBrij	ux	uy	uz
Px	-1.23	0.11	-0.13
Py	0.20	-0.90	-0.07
Pz	-0.01	0.02	-0.28

ZBrij	ux	uy	uz
Px	-1.23	-0.11	-0.13
Py	-0.20	-0.90	0.07
Pz	-0.01	-0.02	-0.28

ZAgij	ux	uy	uz
Px	1.50	-0.19	-0.00
Py	0.14	1.04	0.00
Pz	0.00	0.00	0.35

ZAgij	ux	uy	uz
Px	0.97	-0.39	0.00
Py	-0.24	0.76	-0.00
Pz	0.00	-0.00	0.21

ZBrij	ux	uy	uz
Px	-1.23	0.11	0.13
Py	0.20	-0.90	0.07
Pz	0.01	-0.02	-0.28

ZBrij	ux	uy	uz
Px	-1.23	-0.11	0.13
Py	-0.20	-0.90	-0.07
Pz	0.01	0.02	-0.28

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Ag	0.40
1	Ag	0.40
2	Ag	0.38
3	Ag	0.38
4	Br	-0.39
5	Br	-0.39
6	Br	-0.39
7	Br	-0.39

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	1.605
Interband polarizability (y) [Å]	1.388
Interband polarizability (z) [Å]	0.354

Infrared polarizability

Static polarizability [Å]
Phonons only (x)	2.08
Phonons only (y)	2.20
Phonons only (z)	0.07
Total (phonons + electrons) (x)	3.68
Total (phonons + electrons) (y)	3.59
Total (phonons + electrons) (z)	0.43

Miscellaneous

Miscellaneous details
Unique ID	4AgBr-2
Number of atoms	8
Number of species	2
Formula	Ag4Br4
Reduced formula	AgBr
Stoichiometry	AB
Unit cell area [Å2]	38.113
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree_Wang23/AB/AgBr/Ag4Br4-389f76ad3e2a
Old uid	Ag4Br4-0d12987a1d55
Space group (bulk in AA-stacking)	P2_12_12
Space group number (bulk in AA-stacking)	18
Point group	222
Inversion symmetry	No
Layer group number	21
Layer group	p2_12_12
2D Bravais type	Rectangular (op)
Thickness [Å]	3.275
Structure origin	Wang23
Band gap (PBE) [eV]	2.330
Direct band gap (PBE) [eV]	2.400
gap_dir_nosoc	2.433
Vacuum level [eV]	2.650
Fermi level wrt. vacuum (PBE) [eV]	-5.201
Valence band maximum wrt. vacuum (PBE) [eV]	-6.366
Conduction band minimum wrt. vacuum (PBE) [eV]	-4.036

Miscellaneous details
minhessianeig	-0.000
Dynamically stable	Yes
Band gap (HSE06) [eV]	3.583
Direct band gap (HSE06) [eV]	3.671
Fermi level wrt. vacuum (HSE) [eV]	-5.613
Valence band maximum wrt. vacuum (HSE06) [eV]	-7.405
Conduction band minimum wrt. vacuum (HSE06) [eV]	-3.822
Interband polarizability (x) [Å]	1.605
Interband polarizability (y) [Å]	1.388
Interband polarizability (z) [Å]	0.354
Static polarizability (phonons) (x) [Å]	2.079
Static polarizability (phonons + electrons) (x) [Å]	3.684
Static polarizability (phonons) (y) [Å]	2.204
Static polarizability (phonons + electrons) (y) [Å]	3.592
Static polarizability (phonons) (z) [Å]	0.072
Static polarizability (phonons + electrons) (z) [Å]	0.426
Energy [eV]	-20.434
Magnetic	No
Total magnetic moment [μB]	0.000
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]	0.005
Heat of formation [eV/atom]	-0.342