Overview: Pb₂I₄

Structure info
Layer group	c2/m11
Layer group number	18
Structure origin	Lyngby22_LDP

Stability
Energy above convex hull [eV/atom]	0.073
Heat of formation [eV/atom]	-0.619
Dynamically stable	Yes

Basic properties
Magnetic	No
Out-of-plane dipole [e Å/unit cell]	-0.001
Band gap (PBE) [eV]	1.701
Band gap (HSE) [eV]	2.385

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	8.301	-1.235	0.000	Yes
2	-5.122	6.648	0.000	Yes
3	0.000	0.000	33.223	No

Lengths [Å]	8.392	8.392	33.223
Angles [°]	90.000	90.000	136.072

Crystal structure

Symmetries
2D Bravais type	Centered rectangular (oc)
Layer group number	18
Layer group	c2/m11
Space group number (bulk in AA-stacking)	12
Space group (bulk in AA-stacking)	C2/m
Point group	2/m
Inversion symmetry	Yes

Structure data
Formula	Pb2I4
Stoichiometry	AB2
Number of atoms	6
Unit cell area [Å2]	48.860
Thickness [Å]	4.237

Stability

Convex hull

Pb2I4 (2PbI2-2)
Heat of formation [eV/atom]	-0.62
Energy above convex hull [eV/atom]	0.07

Monolayers from C2DB
PbI2 (1PbI2-1)	-0.69 eV/atom
Pb6I12 (6PbI2-1)	-0.66 eV/atom
Pb2I4 (2PbI2-1)	-0.64 eV/atom
Pb2I4, (2PbI2-2)	-0.62 eV/atom
PbI2 (1PbI2-2)	-0.61 eV/atom
Pb2I4 (2PbI2-3)	-0.60 eV/atom
PbI2 (1PbI2-3)	-0.55 eV/atom
Pb2I2 (2IPb-1)	-0.20 eV/atom
Pb2I2 (2IPb-2)	-0.19 eV/atom

Bulk crystals from OQMD123
Pb4I8	-0.69 eV/atom
I4	0.00 eV/atom
Pb	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Deformation potentials

DVB [eV]	xx	yy	xy
Γ	-1.18	-0.08	1.06
X	-0.88	-1.16	-0.10
A1	-0.96	0.04	0.75
Y	-0.93	-1.54	0.08
kVBM	-0.95	-0.31	0.19

	xx	yy	xy
Band gap [eV]	-0.08	-0.19	-0.37

DCB [eV]	xx	yy	xy
Γ	-2.03	0.80	1.48
X	-0.91	-0.53	-0.10
A1	-1.63	1.40	1.59
Y	-0.92	0.65	0.54
kCBM	-1.03	-0.50	-0.18

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	8.07	5.58	1.21
yy	6.29	7.48	2.22
xy	1.39	0.19	3.47

Stiffness tensor eigenvalues
Eigenvalue 0	2.53 N/m
Eigenvalue 1	2.53 N/m
Eigenvalue 2	13.96 N/m

Electronic bands

Band structure and DOS (PBE)

Properties [eV]
Band gap	1.701
Direct band gap	1.771
VBM wrt. vacuum	-5.959
CBM wrt. vacuum	-4.258
Vacuum level shift	-0.004

Band structure (HSE06@PBE)

Properties [eV]
Band gap	2.385
Direct band gap	2.459
VBM wrt. vacuum	-6.411
CBM wrt. vacuum	-4.026

Effective masses

Property (VBM)	Value
Min eff. mass	0.42 m0
Max eff. mass	1.77 m0
DOS eff. mass	0.86 m0
Crystal coordinates	[-0.271, -0.271]
Warping parameter	-0.002
Barrier height	> 15.5 meV
Distance to barrier	> 0.0145 Å-1

Property (CBM)	Value
Min eff. mass	0.31 m0
Max eff. mass	2.01 m0
DOS eff. mass	0.80 m0
Crystal coordinates	[-0.192, -0.207]
Warping parameter	0.040
Barrier height	> 15.5 meV
Distance to barrier	> 0.0145 Å-1

Born charges

ZPbij	ux	uy	uz
Px	3.59	0.01	0.16
Py	0.01	3.61	-0.10
Pz	0.10	-0.06	0.57

ZIij	ux	uy	uz
Px	-2.07	-0.87	-0.44
Py	-0.87	-3.04	0.26
Pz	-0.09	0.05	-0.15

ZIij	ux	uy	uz
Px	-1.52	0.86	0.28
Py	0.86	-0.57	-0.16
Pz	-0.01	0.01	-0.42

ZIij	ux	uy	uz
Px	-2.07	-0.88	-0.44
Py	-0.88	-3.05	0.26
Pz	-0.09	0.05	-0.15

ZIij	ux	uy	uz
Px	-1.53	0.86	0.28
Py	0.86	-0.57	-0.16
Pz	-0.01	0.01	-0.41

ZPbij	ux	uy	uz
Px	3.60	0.02	0.16
Py	0.02	3.62	-0.09
Pz	0.10	-0.06	0.56

Miscellaneous

Miscellaneous details
Unique ID	2PbI2-2
Number of atoms	6
Number of species	2
Formula	Pb2I4
Reduced formula	PbI2
Stoichiometry	AB2
Unit cell area [Å2]	48.860
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree_LDP/AB2/PbI2/Pb2I4-9a28942c2dcc
Old uid	Pb2I4-a09645eda3b3
Space group (bulk in AA-stacking)	C2/m
Space group number (bulk in AA-stacking)	12
Point group	2/m
Inversion symmetry	Yes
Layer group number	18
Layer group	c2/m11
2D Bravais type	Centered rectangular (oc)
Thickness [Å]	4.237
Structure origin	Lyngby22_LDP
Band gap [eV]	1.701
Direct band gap [eV]	1.771
gap_dir_nosoc	2.524

Miscellaneous details
Vacuum level [eV]	1.346
Fermi level wrt. vacuum [eV]	-5.109
VBM wrt. vacuum [eV]	-5.959
CBM wrt. vacuum [eV]	-4.258
Vacuum level shift [eV]	-0.004
Out-of-plane dipole [e Å/unit cell]	-0.001
minhessianeig	-0.000
Dynamically stable	Yes
Band gap [eV]	2.385
Direct band gap [eV]	2.459
Fermi level wrt. vacuum [eV]	-5.219
VBM wrt. vacuum [eV]	-6.411
CBM wrt. vacuum [eV]	-4.026
Energy [eV]	-17.145
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]	0.073
Heat of formation [eV/atom]	-0.619