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Structure info
Layer group p2/m11
Layer group number 14
Structure origin original03-18
Stability
Energy above convex hull [eV/atom] 0.101
Heat of formation [eV/atom] -0.040
Dynamically stable Yes
Basic properties
Magnetic No
Band gap (PBE) [eV] 0.447
Band gap (HSE06) [eV] 1.116
XYZ CIF JSON
Axis x [Å] y [Å] z [Å] Periodic
1 3.524 0.000 0.000 Yes
2 0.000 5.183 0.000 Yes
3 0.000 0.000 17.509 No
Lengths [Å] 3.524 5.183 17.509
Angles [°] 90.000 90.000 90.000

Symmetries
2D Bravais type Rectangular (op)
Layer group number 14
Layer group p2/m11
Space group number (bulk in AA-stacking) 10
Space group (bulk in AA-stacking) P2/m
Point group 2/m
Inversion symmetry Yes
Structure data
Formula Cu2Se2
Stoichiometry AB
Number of atoms 4
Unit cell area [Å2] 18.266
Thickness [Å] 2.770

Cu2Se2 (2CuSe-4)
Heat of formation [eV/atom] -0.04
Energy above convex hull [eV/atom] 0.10
Monolayers from C2DB
Se2Cu3 (1Se2Cu3-1) -0.11 eV/atom
Se2Cu4 (2SeCu2-1) -0.11 eV/atom
Cu2Se2 (2CuSe-1) -0.09 eV/atom
Cu2Se2 (2CuSe-2) -0.08 eV/atom
Cu2Se2 (2CuSe-3) -0.07 eV/atom
Se5Cu6 (1Se5Cu6-1) -0.07 eV/atom
Se2Cu4 (2SeCu2-2) -0.04 eV/atom
Cu2Se2, (2CuSe-4) -0.04 eV/atom
Cu2Se4 (2CuSe2-1) -0.00 eV/atom
Cu2Se2 (2CuSe-5) 0.02 eV/atom
CuSe2 (1CuSe2-1) 0.03 eV/atom
Cu2Se4 (2CuSe2-2) 0.10 eV/atom
CuSe2 (1CuSe2-2) 0.12 eV/atom
Cu2Se2 (2CuSe-6) 0.12 eV/atom
SeCu2 (1SeCu2-1) 0.14 eV/atom
CuSe2 (1CuSe2-3) 0.17 eV/atom
Se2 (2Se-1) 0.21 eV/atom
Se2 (2Se-2) 0.29 eV/atom
Bulk crystals from OQMD123
Cu6Se4 -0.15 eV/atom
Cu6Se6 -0.14 eV/atom
Cu2Se4 -0.10 eV/atom
Cu 0.00 eV/atom
Se3 0.00 eV/atom

AB/2CuSe/4/phonon_bs.png
Minimum eigenvalue of Hessian [eV/Ų] -0.00

DVB [eV] xx yy xy
Γ 0.56 -3.70 0.00
X -1.98 -1.84 0.00
S -2.62 0.68 0.00
Y -4.44 -0.20 -0.00
kVBM -4.44 -0.20 -0.00
xx yy xy
Band gap [eV] 5.80 0.71 0.00
DCB [eV] xx yy xy
Γ -5.52 0.99 -0.00
X -0.82 0.26 -0.00
S -0.26 1.37 -0.00
Y -6.03 0.46 0.00
kCBM 1.37 0.51 0.00

Cij (N/m) xx yy xy
xx 40.58 -1.30 -0.00
yy -0.68 2.81 -0.00
xy 0.00 0.00 1.92
Stiffness tensor eigenvalues
Eigenvalue 0 1.92 N/m
Eigenvalue 1 2.78 N/m
Eigenvalue 2 40.61 N/m

Key values [eV]
Band gap (PBE) 0.447
Direct band gap (PBE) 0.977
Valence band maximum wrt. vacuum (PBE) -5.413
Conduction band minimum wrt. vacuum (PBE) -4.966
DOS BZ

Key values [eV]
Band gap (HSE06) 1.116
Direct band gap (HSE06) 1.654
Valence band maximum wrt. vacuum (HSE06) -6.278
Conduction band minimum wrt. vacuum (HSE06) -5.162

VBM
Property (VBM) Value
Min eff. mass 0.42 m0
Max eff. mass 0.93 m0
DOS eff. mass 0.63 m0
Crystal coordinates [0.000, 0.500]
Warping parameter -0.001
Barrier height > 83.2 meV
Distance to barrier > 0.0236 Å-1
CBM
Property (CBM) Value
Min eff. mass 0.31 m0
Max eff. mass 2.17 m0
DOS eff. mass 0.81 m0
Crystal coordinates [0.245, 0.000]
Warping parameter 0.003
Barrier height > 34.3 meV
Distance to barrier > 0.0237 Å-1

ZCuij ux uy uz
Px 0.30 -0.00 -0.00
Py -0.00 0.16 -0.21
Pz -0.00 0.08 0.06
ZCuij ux uy uz
Px 2.04 -0.00 -0.00
Py -0.00 0.19 -0.17
Pz -0.00 -0.04 -0.02
ZSeij ux uy uz
Px -1.17 0.00 -0.00
Py 0.00 -0.18 0.19
Pz -0.00 -0.02 -0.02
ZSeij ux uy uz
Px -1.17 -0.00 0.00
Py -0.00 -0.18 0.19
Pz 0.00 -0.02 -0.02

Atom No. Chemical symbol Charges [|e|]
0 Cu 0.31
1 Se -0.36
2 Cu 0.40
3 Se -0.36

AB/2CuSe/4/rpa-pol-x.png AB/2CuSe/4/rpa-pol-z.png
AB/2CuSe/4/rpa-pol-y.png
Properties
Interband polarizability (x) [Å] 8.171
Interband polarizability (y) [Å] 2.760
Interband polarizability (z) [Å] 0.343
Plasma frequency (x) [eV Å0.5] 0.000
Plasma frequency (y) [eV Å0.5] 0.000

AB/2CuSe/4/ir-pol-x.png AB/2CuSe/4/ir-pol-z.png
AB/2CuSe/4/ir-pol-y.png
Static polarizability [Å]
Phonons only (x) 0.33
Phonons only (y) 0.07
Phonons only (z) 0.00
Total (phonons + electrons) (x) 8.50
Total (phonons + electrons) (y) 2.83
Total (phonons + electrons) (z) 0.34

AB/2CuSe/4/absx.png
Exciton binding energy (BSE) [eV] 0.86
AB/2CuSe/4/absz.png

Miscellaneous details
Unique ID 2CuSe-4
Number of atoms 4
Number of species 2
Formula Cu2Se2
Reduced formula CuSe
Stoichiometry AB
Unit cell area [Å2] 18.266
Original file-system folder /home/niflheim2/cmr/C2DB-ASR/tree/AB/CuSe/Cu2Se2-0fb3eda814f3
Old uid Cu2Se2-0fb3eda814f3
Space group (bulk in AA-stacking) P2/m
Space group number (bulk in AA-stacking) 10
Point group 2/m
Inversion symmetry Yes
Layer group number 14
Layer group p2/m11
2D Bravais type Rectangular (op)
Thickness [Å] 2.770
Structure origin original03-18
Band gap (PBE) [eV] 0.447
Direct band gap (PBE) [eV] 0.977
gap_dir_nosoc 0.989
Vacuum level [eV] 2.595
Fermi level wrt. vacuum (PBE) [eV] -5.189
Valence band maximum wrt. vacuum (PBE) [eV] -5.413
Conduction band minimum wrt. vacuum (PBE) [eV] -4.966
minhessianeig -0.003
Miscellaneous details
Dynamically stable Yes
Band gap (HSE06) [eV] 1.116
Direct band gap (HSE06) [eV] 1.654
Fermi level wrt. vacuum (HSE) [eV] -5.748
Valence band maximum wrt. vacuum (HSE06) [eV] -6.278
Conduction band minimum wrt. vacuum (HSE06) [eV] -5.162
E_B 0.859
Interband polarizability (x) [Å] 8.171
Interband polarizability (y) [Å] 2.760
Interband polarizability (z) [Å] 0.343
Static polarizability (phonons) (x) [Å] 0.329
Static polarizability (phonons + electrons) (x) [Å] 8.500
Static polarizability (phonons) (y) [Å] 0.069
Static polarizability (phonons + electrons) (y) [Å] 2.829
Static polarizability (phonons) (z) [Å] 0.001
Static polarizability (phonons + electrons) (z) [Å] 0.345
Plasma frequency (x) [eV Å0.5] 0.000
Plasma frequency (y) [eV Å0.5] 0.000
Energy [eV] -14.479
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] 0.101
Heat of formation [eV/atom] -0.040