Overview: Pb₂I₄

Structure info
Layer group	pmma
Layer group number	41
Structure origin	Wang23

Stability
Energy above convex hull [eV/atom]	0.094
Heat of formation [eV/atom]	-0.599
Dynamically stable	No

Basic properties
Magnetic	No
Out-of-plane dipole [e Å/unit cell]	-0.000
Band gap (PBE) [eV]	1.191

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	8.858	-0.000	0.000	Yes
2	0.000	4.302	0.000	Yes
3	0.000	-0.000	22.381	No

Lengths [Å]	8.858	4.302	22.381
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	41
Layer group	pmma
Space group number (bulk in AA-stacking)	51
Space group (bulk in AA-stacking)	Pmma
Point group	mmm
Inversion symmetry	Yes

Structure data
Formula	Pb2I4
Stoichiometry	AB2
Number of atoms	6
Unit cell area [Å2]	38.106
Thickness [Å]	7.302

Stability

Convex hull

Pb2I4 (2PbI2-3)
Heat of formation [eV/atom]	-0.60
Energy above convex hull [eV/atom]	0.09

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]

-0.21

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	7.12	3.73	-0.00
yy	4.00	29.61	-0.00
xy	0.00	0.00	9.25

Stiffness tensor eigenvalues
Eigenvalue 0	6.48 N/m
Eigenvalue 1	9.25 N/m
Eigenvalue 2	30.25 N/m

Band structure and DOS (PBE)

Properties [eV]
Band gap	1.191
Direct band gap	1.348
VBM wrt. vacuum	-6.284
CBM wrt. vacuum	-5.093
Vacuum level shift	-0.000

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Pb	0.95
1	Pb	0.95
2	I	-0.42
3	I	-0.42
4	I	-0.53
5	I	-0.53

Miscellaneous

Miscellaneous details
Unique ID	2PbI2-3
Number of atoms	6
Number of species	2
Formula	Pb2I4
Reduced formula	PbI2
Stoichiometry	AB2
Unit cell area [Å2]	38.106
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree_Wang23/AB2/PbI2/Pb2I4-257e6f2a6471
Old uid	Pb2I4-45d5c2d51311
Space group (bulk in AA-stacking)	Pmma
Space group number (bulk in AA-stacking)	51
Point group	mmm
Inversion symmetry	Yes
Layer group number	41
Layer group	pmma
2D Bravais type	Rectangular (op)
Thickness [Å]	7.302
Structure origin	Wang23
Band gap [eV]	1.191

Miscellaneous details
Direct band gap [eV]	1.348
gap_dir_nosoc	1.851
Vacuum level [eV]	2.649
Fermi level wrt. vacuum [eV]	-5.688
VBM wrt. vacuum [eV]	-6.284
CBM wrt. vacuum [eV]	-5.093
Vacuum level shift [eV]	-0.000
Out-of-plane dipole [e Å/unit cell]	-0.000
minhessianeig	-0.207
Dynamically stable	No
Energy [eV]	-17.022
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]	0.094
Heat of formation [eV/atom]	-0.599