Overview: Ag₂Cu₂Se₂

Structure info
Layer group	pm2_1b
Layer group number	28
Structure origin	Wang23

Stability
Energy above convex hull [eV/atom]	0.054
Heat of formation [eV/atom]	-0.059
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	4.067	0.000	0.000	Yes
2	0.000	4.694	0.000	Yes
3	0.000	0.000	19.077	No

Lengths [Å]	4.067	4.694	19.077
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	28
Layer group	pm2_1b
Space group number (bulk in AA-stacking)	26
Space group (bulk in AA-stacking)	Pmc2_1
Point group	mm2
Inversion symmetry	No

Structure data
Formula	Ag2Cu2Se2
Stoichiometry	ABC
Number of atoms	6
Unit cell area [Å2]	19.088
Thickness [Å]	4.086

Stability

Convex hull

Ag2Cu2Se2 (2AgCuSe-2)
Heat of formation [eV/atom]	-0.06
Energy above convex hull [eV/atom]	0.05

Monolayers from C2DB
Se2Cu3 (1Se2Cu3-1)	-0.11 eV/atom
Se2Cu4 (2SeCu2-1)	-0.11 eV/atom
Se2Ag4 (2SeAg2-1)	-0.09 eV/atom
Cu2Se2 (2CuSe-1)	-0.09 eV/atom
Cu2Se2 (2CuSe-2)	-0.08 eV/atom
Ag2Cu2Se2 (2AgCuSe-1)	-0.07 eV/atom
Cu2Se2 (2CuSe-3)	-0.07 eV/atom
Se8Ag16 (8SeAg2-1)	-0.07 eV/atom
Se5Cu6 (1Se5Cu6-1)	-0.07 eV/atom
Ag2Cu2Se2, (2AgCuSe-2)	-0.06 eV/atom
AgCu2Se2 (1AgCu2Se2-1)	-0.06 eV/atom
Se2Cu4 (2SeCu2-2)	-0.04 eV/atom
Cu2Se2 (2CuSe-4)	-0.04 eV/atom
Ag4Se4 (4AgSe-1)	-0.02 eV/atom
Cu2Se4 (2CuSe2-1)	-0.00 eV/atom
Cu2Se2 (2CuSe-5)	0.02 eV/atom
Ag2Se2 (2AgSe-1)	0.02 eV/atom
CuSe2 (1CuSe2-1)	0.03 eV/atom
Ag8Se12 (4Ag2Se3-1)	0.03 eV/atom
AgCuSe2 (1AgCuSe2-1)	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
AgCuSe2 (1AgCuSe2-2)	0.08 eV/atom
Cu2Se4 (2CuSe2-2)	0.10 eV/atom
AgSe2 (1AgSe2-1)	0.11 eV/atom
CuSe2 (1CuSe2-2)	0.12 eV/atom
Cu2Se2 (2CuSe-6)	0.12 eV/atom
SeCu2 (1SeCu2-1)	0.14 eV/atom
SeAg2 (1SeAg2-1)	0.15 eV/atom
Ag2Se2 (2AgSe-4)	0.15 eV/atom
CuSe2 (1CuSe2-3)	0.17 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
Cu6Se4	-0.15 eV/atom
Cu6Se6	-0.14 eV/atom
Cu2Se4	-0.10 eV/atom
Ag8Se4	-0.07 eV/atom
Ag4	0.00 eV/atom
Cu	0.00 eV/atom
Se3	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.34

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	39.00	-4.67	-0.12
yy	-3.52	73.81	0.17
xy	0.00	-0.00	1.40

Stiffness tensor eigenvalues
Eigenvalue 0	1.40 N/m
Eigenvalue 1	38.54 N/m
Eigenvalue 2	74.27 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)	-4.642

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Cu	0.26
1	Cu	0.26
2	Se	-0.43
3	Se	-0.43
4	Ag	0.17
5	Ag	0.17

Miscellaneous

Miscellaneous details
Unique ID	2AgCuSe-2
Number of atoms	6
Number of species	3
Formula	Ag2Cu2Se2
Reduced formula	AgCuSe
Stoichiometry	ABC
Unit cell area [Å2]	19.088
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree_Wang23/ABC/AgCuSe/Ag2Cu2Se2-98d2144f5c17
Old uid	Ag2Cu2Se2-7e8100fe98f0
Space group (bulk in AA-stacking)	Pmc2_1
Space group number (bulk in AA-stacking)	26
Point group	mm2
Inversion symmetry	No
Layer group number	28
Layer group	pm2_1b
2D Bravais type	Rectangular (op)
Thickness [Å]	4.086

Miscellaneous details
Structure origin	Wang23
Band gap (PBE) [eV]	0.000
Direct band gap (PBE) [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	3.512
Fermi level wrt. vacuum (PBE) [eV]	-4.642
minhessianeig	-0.338
Dynamically stable	No
Energy [eV]	-20.351
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]	0.054
Heat of formation [eV/atom]	-0.059