Overview: Ag₂Se₄

Structure info
Layer group	p2_1/b11
Layer group number	17
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.093
Heat of formation [eV/atom]	0.048
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	6.149	0.000	0.000	Yes
2	0.000	6.375	0.000	Yes
3	-0.000	0.000	16.474	No

Lengths [Å]	6.149	6.375	16.474
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	17
Layer group	p2_1/b11
Space group number (bulk in AA-stacking)	14
Space group (bulk in AA-stacking)	P2_1/c
Point group	2/m
Inversion symmetry	Yes

Structure data
Formula	Ag2Se4
Stoichiometry	AB2
Number of atoms	6
Unit cell area [Å2]	39.201
Thickness [Å]	1.339

Stability

Convex hull

Ag2Se4 (2AgSe2-1)
Heat of formation [eV/atom]	0.05
Energy above convex hull [eV/atom]	0.09

Monolayers from C2DB
Se2Ag4 (2SeAg2-1)	-0.09 eV/atom
Se8Ag16 (8SeAg2-1)	-0.07 eV/atom
Ag4Se4 (4AgSe-1)	-0.02 eV/atom
Ag2Se2 (2AgSe-1)	0.02 eV/atom
Ag8Se12 (4Ag2Se3-1)	0.03 eV/atom
Ag2Se4, (2AgSe2-1)	0.05 eV/atom
Ag2Se2 (2AgSe-2)	0.05 eV/atom
Ag2Se2 (2AgSe-3)	0.06 eV/atom
AgSe2 (1AgSe2-1)	0.11 eV/atom
SeAg2 (1SeAg2-1)	0.15 eV/atom
Ag2Se2 (2AgSe-4)	0.15 eV/atom
Ag2Se2 (2AgSe-5)	0.18 eV/atom
Ag2Se4 (2AgSe2-2)	0.19 eV/atom
Se2 (2Se-1)	0.21 eV/atom
AgSe2 (1AgSe2-2)	0.22 eV/atom
Ag2Se2 (2AgSe-6)	0.27 eV/atom
Se2 (2Se-2)	0.29 eV/atom
Ag2 (2Ag-1)	0.31 eV/atom
AgSe2 (1AgSe2-3)	0.32 eV/atom

Bulk crystals from OQMD123
Ag8Se4	-0.07 eV/atom
Ag4	0.00 eV/atom
Se3	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.70

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	17.82	4.79	-0.00
yy	5.92	22.13	-0.00
xy	0.00	0.00	15.73

Stiffness tensor eigenvalues
Eigenvalue 0	14.23 N/m
Eigenvalue 1	15.73 N/m
Eigenvalue 2	25.72 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)	-4.728

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Ag	0.32
1	Ag	0.32
2	Se	-0.16
3	Se	-0.16
4	Se	-0.16
5	Se	-0.16

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	21.158
Interband polarizability (y) [Å]	34.564
Interband polarizability (z) [Å]	0.248
Plasma frequency (x) [eV Å0.5]	2.803
Plasma frequency (y) [eV Å0.5]	5.561

Miscellaneous

Miscellaneous details
Unique ID	2AgSe2-1
Number of atoms	6
Number of species	2
Formula	Ag2Se4
Reduced formula	AgSe2
Stoichiometry	AB2
Unit cell area [Å2]	39.201
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/AgSe2/Ag2Se4-97844dbedcd4
Old uid	Ag2Se4-97844dbedcd4
Space group (bulk in AA-stacking)	P2_1/c
Space group number (bulk in AA-stacking)	14
Point group	2/m
Inversion symmetry	Yes
Layer group number	17
Layer group	p2_1/b11
2D Bravais type	Rectangular (op)
Thickness [Å]	1.339
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]	2.292
Fermi level wrt. vacuum (PBE) [eV]	-4.728
minhessianeig	-0.697
Dynamically stable	No
Interband polarizability (x) [Å]	21.158
Interband polarizability (y) [Å]	34.564
Interband polarizability (z) [Å]	0.248
Plasma frequency (x) [eV Å0.5]	2.803
Plasma frequency (y) [eV Å0.5]	5.561
Energy [eV]	-19.321
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]	0.093
Heat of formation [eV/atom]	0.048