Overview: Cu₂S₂

Structure info
Layer group	p-3m1
Layer group number	72
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.111
Heat of formation [eV/atom]	-0.101
Dynamically stable	Yes

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	3.803	-0.000	0.000	Yes
2	-1.901	3.295	0.000	Yes
3	0.000	0.000	18.856	No

Lengths [Å]	3.803	3.805	18.856
Angles [°]	90.000	90.000	119.985

Crystal structure

Symmetries
2D Bravais type	Hexagonal (hp)
Layer group number	72
Layer group	p-3m1
Space group number (bulk in AA-stacking)	164
Space group (bulk in AA-stacking)	P-3m1
Point group	-3m
Inversion symmetry	Yes

Structure data
Formula	Cu2S2
Stoichiometry	AB
Number of atoms	4
Unit cell area [Å2]	12.532
Thickness [Å]	2.911

Stability

Convex hull

Cu2S2 (2CuS-1)
Heat of formation [eV/atom]	-0.10
Energy above convex hull [eV/atom]	0.11

Monolayers from C2DB
S4Cu6 (2S2Cu3-1)	-0.21 eV/atom
S4Cu6 (2S2Cu3-2)	-0.21 eV/atom
S2Cu4 (2SCu2-1)	-0.16 eV/atom
S2Cu4 (2SCu2-2)	-0.13 eV/atom
S4Cu6 (2S2Cu3-3)	-0.12 eV/atom
S4Cu6 (2S2Cu3-4)	-0.11 eV/atom
S6Cu12 (6SCu2-1)	-0.10 eV/atom
Cu2S2, (2CuS-1)	-0.10 eV/atom
Cu2S2 (2CuS-2)	-0.09 eV/atom
Cu2S2 (2CuS-3)	-0.05 eV/atom
Cu2S4 (2CuS2-1)	-0.03 eV/atom
Cu2S2 (2CuS-4)	-0.00 eV/atom
Cu2S2 (2CuS-5)	0.03 eV/atom
Cu2S2 (2CuS-6)	0.04 eV/atom
SCu2 (1SCu2-1)	0.12 eV/atom
Cu4S14 (2Cu2S7-1)	0.15 eV/atom
CuS2 (1CuS2-1)	0.16 eV/atom
CuS2 (1CuS2-2)	0.22 eV/atom
Cu2S5 (1Cu2S5-1)	0.27 eV/atom
CuS2 (1CuS2-3)	0.28 eV/atom
S2 (2S-1)	0.45 eV/atom
S2 (2S-2)	0.62 eV/atom

Bulk crystals from OQMD123
Cu6S6	-0.21 eV/atom
Cu2S4	-0.12 eV/atom
Cu	0.00 eV/atom
S48	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	58.22	34.47	-0.05
yy	34.41	59.03	0.03
xy	0.08	0.01	21.87

Stiffness tensor eigenvalues
Eigenvalue 0	21.87 N/m
Eigenvalue 1	24.19 N/m
Eigenvalue 2	93.07 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)	-5.612

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	S	-0.59
1	S	-0.59
2	Cu	0.59
3	Cu	0.59

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	29.913
Interband polarizability (y) [Å]	29.493
Interband polarizability (z) [Å]	0.397
Plasma frequency (x) [eV Å0.5]	8.224
Plasma frequency (y) [eV Å0.5]	8.277

Raman spectrum

Mode	Frequency (1/cm)	Degeneracy
Mode 1	0.1	3
Mode 2	65.	2
Mode 3	121.7	1
Mode 4	240.8	1
Mode 5	260.6	1
Mode 6	294.8	2
Mode 7	300.8	2

Miscellaneous

Miscellaneous details
Unique ID	2CuS-1
Number of atoms	4
Number of species	2
Formula	Cu2S2
Reduced formula	CuS
Stoichiometry	AB
Unit cell area [Å2]	12.532
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB/CuS/Cu2S2-9077db3386d7
Old uid	Cu2S2-9077db3386d7
Space group (bulk in AA-stacking)	P-3m1
Space group number (bulk in AA-stacking)	164
Point group	-3m
Inversion symmetry	Yes
Layer group number	72
Layer group	p-3m1
2D Bravais type	Hexagonal (hp)
Thickness [Å]	2.911
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]	3.123
Fermi level wrt. vacuum (PBE) [eV]	-5.612
minhessianeig	-0.000
Dynamically stable	Yes
Interband polarizability (x) [Å]	29.913
Interband polarizability (y) [Å]	29.493
Interband polarizability (z) [Å]	0.397
Plasma frequency (x) [eV Å0.5]	8.224
Plasma frequency (y) [eV Å0.5]	8.277
Energy [eV]	-15.913
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]	0.111
Heat of formation [eV/atom]	-0.101