Overview: Ag₂Cu₂Se₂

Structure info
Layer group	cm2e
Layer group number	36
Structure origin	Wang23

Stability
Energy above convex hull [eV/atom]	0.039
Heat of formation [eV/atom]	-0.074
Dynamically stable	No

Basic properties
Magnetic	No
Band gap (PBE) [eV]	0.475

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	4.897	0.023	0.000	Yes
2	-2.469	4.017	0.000	Yes
3	0.000	-0.000	18.955	No

Lengths [Å]	4.897	4.715	18.955
Angles [°]	90.000	90.000	121.305

Crystal structure

Symmetries
2D Bravais type	Centered rectangular (oc)
Layer group number	36
Layer group	cm2e
Space group number (bulk in AA-stacking)	39
Space group (bulk in AA-stacking)	Aem2
Point group	mm2
Inversion symmetry	No

Structure data
Formula	Ag2Cu2Se2
Stoichiometry	ABC
Number of atoms	6
Unit cell area [Å2]	19.730
Thickness [Å]	3.968

Stability

Convex hull

Ag2Cu2Se2 (2AgCuSe-1)
Heat of formation [eV/atom]	-0.07
Energy above convex hull [eV/atom]	0.04

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]

-0.29

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	46.94	5.96	-0.01
yy	5.65	28.81	0.02
xy	0.33	0.13	16.36

Stiffness tensor eigenvalues
Eigenvalue 0	16.36 N/m
Eigenvalue 1	27.11 N/m
Eigenvalue 2	48.64 N/m

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	0.475
Direct band gap (PBE)	0.475
Valence band maximum wrt. vacuum (PBE)	-4.893
Conduction band minimum wrt. vacuum (PBE)	-4.418

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Cu	0.23
1	Cu	0.23
2	Ag	0.22
3	Ag	0.22
4	Se	-0.45
5	Se	-0.45

Miscellaneous

Miscellaneous details
Unique ID	2AgCuSe-1
Number of atoms	6
Number of species	3
Formula	Ag2Cu2Se2
Reduced formula	AgCuSe
Stoichiometry	ABC
Unit cell area [Å2]	19.730
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree_Wang23/ABC/AgCuSe/Ag2Cu2Se2-040bfbebdbb3
Old uid	Ag2Cu2Se2-11cf11399f51
Space group (bulk in AA-stacking)	Aem2
Space group number (bulk in AA-stacking)	39
Point group	mm2
Inversion symmetry	No
Layer group number	36
Layer group	cm2e
2D Bravais type	Centered rectangular (oc)
Thickness [Å]	3.968
Structure origin	Wang23

Miscellaneous details
Band gap (PBE) [eV]	0.475
Direct band gap (PBE) [eV]	0.475
gap_dir_nosoc	0.501
Vacuum level [eV]	3.338
Fermi level wrt. vacuum (PBE) [eV]	-4.655
Valence band maximum wrt. vacuum (PBE) [eV]	-4.893
Conduction band minimum wrt. vacuum (PBE) [eV]	-4.418
minhessianeig	-0.289
Dynamically stable	No
Energy [eV]	-20.440
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]	0.039
Heat of formation [eV/atom]	-0.074