Overview: Pb₂I₂

Structure info
Layer group	p4/nmm
Layer group number	64
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.322
Heat of formation [eV/atom]	-0.197
Dynamically stable	No

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

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	4.607	-0.000	0.000	Yes
2	0.000	4.607	0.000	Yes
3	-0.000	0.000	19.031	No

Lengths [Å]	4.607	4.607	19.031
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Square (tp)
Layer group number	64
Layer group	p4/nmm
Space group number (bulk in AA-stacking)	129
Space group (bulk in AA-stacking)	P4/nmm
Point group	4/mmm
Inversion symmetry	Yes

Structure data
Formula	Pb2I2
Stoichiometry	AB
Number of atoms	4
Unit cell area [Å2]	21.225
Thickness [Å]	5.200

Stability

Convex hull

I2Pb2 (2IPb-1)
Heat of formation [eV/atom]	-0.20
Energy above convex hull [eV/atom]	0.32

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]

-1.01

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	-43.03	56.96	0.00
yy	56.45	-42.31	0.00
xy	0.00	-0.00	11.09

Stiffness tensor eigenvalues
Eigenvalue 0	-99.38 N/m
Eigenvalue 1	11.09 N/m
Eigenvalue 2	14.04 N/m

Electronic bands

Band structure and DOS (PBE)

Properties [eV]
Band gap	0.000
Direct band gap	0.000
Vacuum level shift	0.000
Fermi level wrt. vacuum	-5.730

Fermi surface

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	I	-0.44
1	I	-0.44
2	Pb	0.44
3	Pb	0.44

Miscellaneous

Miscellaneous details
Unique ID	2IPb-1
Number of atoms	4
Number of species	2
Formula	Pb2I2
Reduced formula	PbI
Stoichiometry	AB
Unit cell area [Å2]	21.225
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB/IPb/I2Pb2-bea8b51f9b9f
Old uid	I2Pb2-bea8b51f9b9f
Space group (bulk in AA-stacking)	P4/nmm
Space group number (bulk in AA-stacking)	129
Point group	4/mmm
Inversion symmetry	Yes
Layer group number	64
Layer group	p4/nmm
2D Bravais type	Square (tp)
Thickness [Å]	5.200

Miscellaneous details
Structure origin	original03-18
Band gap [eV]	0.000
Direct band gap [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	3.784
Fermi level wrt. vacuum [eV]	-5.730
Vacuum level shift [eV]	0.000
Out-of-plane dipole [e Å/unit cell]	0.000
minhessianeig	-1.013
Dynamically stable	No
Energy [eV]	-11.262
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]	0.322
Heat of formation [eV/atom]	-0.197