Overview: In₂Se₂

Structure info
Layer group	p4/mmm
Layer group number	61
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.305
Heat of formation [eV/atom]	-0.232
Dynamically stable	No

Basic properties
Magnetic	No
Band gap (PBE) [eV]	0.000

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	5.648	-0.000	0.000	Yes
2	0.000	5.648	0.000	Yes
3	0.000	0.000	15.000	No

Lengths [Å]	5.648	5.648	15.000
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Square (tp)
Layer group number	61
Layer group	p4/mmm
Space group number (bulk in AA-stacking)	123
Space group (bulk in AA-stacking)	P4/mmm
Point group	4/mmm
Inversion symmetry	Yes

Structure data
Formula	In2Se2
Stoichiometry	AB
Number of atoms	4
Unit cell area [Å2]	31.902
Thickness [Å]	0.000

Stability

Convex hull

In2Se2 (2InSe-6)
Heat of formation [eV/atom]	-0.23
Energy above convex hull [eV/atom]	0.31

Monolayers from C2DB
In2Se2 (2InSe-1)	-0.54 eV/atom
In2Se2 (2InSe-2)	-0.53 eV/atom
In4Se6 (2In2Se3-1)	-0.53 eV/atom
In2Se3 (1In2Se3-1)	-0.53 eV/atom
In8Se12 (4In2Se3-1)	-0.51 eV/atom
In3Se4 (1In3Se4-1)	-0.51 eV/atom
In2Se2 (2InSe-3)	-0.50 eV/atom
In2Se3 (1In2Se3-2)	-0.50 eV/atom
Se12In13 (1Se12In13-1)	-0.49 eV/atom
In2Se3 (1In2Se3-3)	-0.48 eV/atom
Se12In14 (2Se6In7-1)	-0.44 eV/atom
Se12In15 (3Se4In5-1)	-0.42 eV/atom
In2Se2 (2InSe-4)	-0.39 eV/atom
In2Se5 (1In2Se5-1)	-0.36 eV/atom
In2Se2 (2InSe-5)	-0.29 eV/atom
In2Se2, (2InSe-6)	-0.23 eV/atom
In2Se4 (2InSe2-1)	-0.22 eV/atom
InSe2 (1InSe2-1)	-0.21 eV/atom
In2Se3 (1In2Se3-4)	-0.16 eV/atom
In2Se4 (2InSe2-2)	-0.16 eV/atom
In2Se4 (2InSe2-3)	-0.11 eV/atom
In2Se4 (2InSe2-4)	-0.04 eV/atom
InSe4 (1InSe4-1)	0.04 eV/atom
Se2 (2Se-1)	0.21 eV/atom
Se2 (2Se-2)	0.29 eV/atom

Bulk crystals from OQMD123
In4Se4	-0.53 eV/atom
In12Se18	-0.53 eV/atom
In	0.00 eV/atom
Se3	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	22.66	43.13	0.00
yy	43.13	22.66	0.00
xy	0.00	0.00	19.79

Stiffness tensor eigenvalues
Eigenvalue 0	-20.47 N/m
Eigenvalue 1	19.79 N/m
Eigenvalue 2	65.78 N/m

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	0.000
Direct band gap (PBE)	0.000
Fermi level wrt. vacuum (PBE)	-4.013

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	In	0.75
1	In	0.75
2	Se	-0.75
3	Se	-0.75

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	2.014
Interband polarizability (y) [Å]	2.014
Interband polarizability (z) [Å]	0.221
Plasma frequency (x) [eV Å0.5]	10.483
Plasma frequency (y) [eV Å0.5]	10.483

Raman spectrum

Mode	Frequency (1/cm)	Degeneracy
Mode 1	0.1	3
Mode 2	16.	1
Mode 3	29.8	1
Mode 4	61.	2
Mode 5	67.3	1
Mode 6	128.3	2
Mode 7	165.	2

Miscellaneous

Miscellaneous details
Unique ID	2InSe-6
Number of atoms	4
Number of species	2
Formula	In2Se2
Reduced formula	InSe
Stoichiometry	AB
Unit cell area [Å2]	31.902
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB/InSe/In2Se2-80128895cd2d
Old uid	In2Se2-80128895cd2d
Space group (bulk in AA-stacking)	P4/mmm
Space group number (bulk in AA-stacking)	123
Point group	4/mmm
Inversion symmetry	Yes
Layer group number	61
Layer group	p4/mmm
2D Bravais type	Square (tp)
Thickness [Å]	0.000
Structure origin	original03-18
Band gap (PBE) [eV]	0.000

Miscellaneous details
Direct band gap (PBE) [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	2.234
Fermi level wrt. vacuum (PBE) [eV]	-4.013
minhessianeig	-0.000
Dynamically stable	No
Interband polarizability (x) [Å]	2.014
Interband polarizability (y) [Å]	2.014
Interband polarizability (z) [Å]	0.221
Plasma frequency (x) [eV Å0.5]	10.483
Plasma frequency (y) [eV Å0.5]	10.483
Energy [eV]	-13.421
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]	0.305
Heat of formation [eV/atom]	-0.232