Atoms: SiSe₂

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

Stability
Energy above convex hull [eV/atom]	0.116
Heat of formation [eV/atom]	-0.334
Dynamically stable	Yes

Basic properties
Magnetic state	NM
Band gap [eV]	0.467
Band gap (HSE06) [eV]	1.072
Band gap (G₀W₀) [eV]	1.803

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	3.508	-0.000	0.000	Yes
2	-1.754	3.039	0.000	Yes
3	0.000	0.000	18.246	No

Lengths [Å]	3.508	3.509	18.246
Angles [°]	90.000	90.000	119.985

Convex hull

SiSe2 (1SiSe2-2)
Heat of formation [eV/atom]	-0.33
Energy above convex hull [eV/atom]	0.12

Monolayers from C2DB
Si4Se8, (4SiSe2-1)	-0.45 eV/atom
Si4Se8, (4SiSe2-2)	-0.39 eV/atom
SiSe2, (1SiSe2-1)	-0.37 eV/atom
SiSe2, (1SiSe2-2)	-0.33 eV/atom
SeSi, (1SeSi-1)	0.05 eV/atom
Se2Si2, (2SeSi-1)	0.06 eV/atom
SiSe2, (1SiSe2-3)	0.07 eV/atom
Se2, (2Se-1)	0.21 eV/atom
Se2, (2Se-2)	0.29 eV/atom
Se2Si2, (2SeSi-2)	0.47 eV/atom
Si2, (2Si-1)	0.64 eV/atom

Bulk crystals from OQMD123
Se4Si2	-0.45 eV/atom
Se3	0.00 eV/atom
Si2	0.00 eV/atom

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	93.25	22.31	-0.03
yy	21.88	93.34	-0.07
xy	-0.02	-0.05	71.01

Stiffness tensor eigenvalues
Eigenvalue 0	71.01 N/m
Eigenvalue 1	71.20 N/m
Eigenvalue 2	115.38 N/m

Phonons

Property	Value
Minimum eigenvalue of Hessian [eV/Ų]	-0.00

Deformation potentials

DVB (eV)	xx	yy	xy
Γ	-6.68	-6.37	-0.03
Y	-8.82	2.85	-0.03
H	-6.68	-6.37	-0.03
C	-0.16	-5.80	-5.02
H1	-6.68	-6.37	-0.03
X	-0.16	-5.81	4.95
kVBM	-9.16	-2.90	-0.04

	xx	yy	xy
Band Gap	8.61	-3.66	5.30

DCB (eV)	xx	yy	xy
Γ	-12.21	-12.10	-0.03
Y	-9.72	2.61	-0.03
H	-12.21	-12.10	-0.03
C	-0.54	-6.55	-5.32
H1	-12.21	-12.10	-0.03
X	-0.55	-6.56	5.26
kCBM	-0.55	-6.56	5.26

Band structure and DOS

Effective masses

Property (VBM)	Value
Min eff. mass	0.16 m0
Max eff. mass	0.87 m0
DOS eff. mass	0.37 m0
Crystal coordinates	[-0.000, 0.136]
Warping parameter	-0.000
Barrier height	> 62.5 meV
Distance to barrier	> 0.0206 Å-1

Property (CBM)	Value
Min eff. mass	0.15 m0
Max eff. mass	0.64 m0
DOS eff. mass	0.31 m0
Crystal coordinates	[0.500, -0.500]
Warping parameter	0.003
Barrier height	> 101.8 meV
Distance to barrier	> 0.0207 Å-1

Electronic band structure (HSE06@PBE)

Property	Value
KVP: Band gap (HSE06) [eV]	1.07
KVP: Direct band gap (HSE06) [eV]	1.73
Valence band maximum wrt. vacuum level (HSE06)	-6.08 eV
Conduction band minimum wrt. vacuum level (HSE06)	-5.01 eV

Electronic band structure (G₀W₀@PBE)

Property	Value
Band gap (G₀W₀) [eV]	1.80
Direct band gap (G₀W₀) [eV]	2.43
Valence band maximum wrt. vacuum level (G₀W₀)	-6.57 eV
Conduction band minimum wrt. vacuum level (G₀W₀)	-4.77 eV

Born charges

ZSiij	ux	uy	uz
Px	4.35	0.00	0.01
Py	0.00	4.35	-0.00
Pz	-0.00	0.00	0.34

ZSeij	ux	uy	uz
Px	-2.18	-0.00	-0.00
Py	-0.00	-2.18	0.00
Pz	-0.00	0.00	-0.17

ZSeij	ux	uy	uz
Px	-2.17	-0.00	-0.00
Py	-0.00	-2.18	0.00
Pz	0.00	-0.00	-0.17

Optical polarizability

Properties
Static interband polarizability at (x) [Å]	4.613
Static interband polarizability at (y) [Å]	4.592
Static interband polarizability at (z) [Å]	0.388
Plasma frequency (x) [Å0.5]	0.000
Plasma frequency (y) [Å0.5]	0.000

Infrared polarizability

Static polarizability	[Å]
Phonons only (x)	3.81
Phonons only (y)	3.82
Phonons only (z)	0.01
Total (phonons + electrons) (x)	8.42
Total (phonons + electrons) (y)	8.42
Total (phonons + electrons) (z)	0.40

Bader charges

#	Chemical symbol	Charges [|e|]
0	Si	1.59
1	Se	-0.79
2	Se	-0.80

Piezoelectric tensor

cij (e/Ådim-1)	xx	yy	xy
x	-0.00	0.00	0.00
y	0.00	0.00	-0.00
z	-0.00	0.00	0.00

cclampedij (e/Ådim-1)	xx	yy	xy
x	-0.00	0.00	0.00
y	-0.00	0.00	-0.00
z	0.00	-0.00	-0.00

Miscellaneous

Miscellaneous details
Unique ID	1SiSe2-2
Number of atoms	3
Number of species	2
Formula	SiSe2
Reduced formula	SiSe2
Stoichiometry	AB2
Unit cell area [Å2]	10.663
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/SiSe2/SiSe2-0dae128e0ffe
Old uid	SiSe2-0dae128e0ffe
Inversion symmetry	Yes
Layer group	p-3m1
Layer group number	72
Structure origin	original03-18
Band gap [eV]	0.467
gap_dir	1.068
gap_dir_nosoc	1.083
Vacuum level [eV]	3.756
Fermi level [eV]	-1.652
minhessianeig	-0.000
Dynamically stable	Yes
Band gap (HSE06) [eV]	1.072
gap_dir_hse	1.734
vbm_hse	-2.323

Miscellaneous details
cbm_hse	-1.251
Band gap (G₀W₀) [eV]	1.803
gap_dir_gw	2.425
vbm_gw	-2.814
cbm_gw	-1.011
Static interband polarizability at (x) [Å]	4.613
Static interband polarizability at (y) [Å]	4.592
Static interband polarizability at (z) [Å]	0.388
Static polarizability (phonons) (x) [Å]	3.809
Static polarizability (phonons + electrons) (x) [Å]	8.421
Static polarizability (phonons) (y) [Å]	3.824
Static polarizability (phonons + electrons) (y) [Å]	8.416
Static polarizability (phonons) (z) [Å]	0.008
Static polarizability (phonons + electrons) (z) [Å]	0.396
Plasma frequency (x) [Å0.5]	0.000
Plasma frequency (y) [Å0.5]	0.000
Energy [eV]	-13.367
Magnetic state	NM
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]	0.116
Heat of formation [eV/atom]	-0.334