1TiI2-2

Atoms: TiI₂ Convex hull Stiffness tensor Phonons Deformation potentials Band structure and DOS Effective masses Electronic band structure (HSE06@PBE) Electronic band structure (G₀W₀@PBE) Born charges Second harmonic generation Optical polarizability Infrared polarizability Raman spectrum Optical absorption (BSE and RPA) Bader charges Piezoelectric tensor Shift current Miscellaneous

Structure info
Layer group	p-6m2
Layer group number	78
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.052
Heat of formation [eV/atom]	-0.670
Dynamically stable	Yes

Basic properties
Magnetic state	NM
Band gap [eV]	0.596
Band gap (HSE06) [eV]	0.828
Band gap (G₀W₀) [eV]	1.090

Repeat: Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	3.769	0.000	0.000	Yes
2	-1.884	3.264	0.000	Yes
3	0.000	0.000	18.629	No

Lengths [Å]	3.769	3.769	18.629
Angles [°]	90.000	90.000	120.000

TiI₂ (1TiI2-2)
Heat of formation [eV/atom]	-0.67
Energy above convex hull [eV/atom]	0.05

Monolayers from C2DB
Ti₂I₆, (2TiI3-1)	-0.80 eV/atom
Ti₂I₆, (2TiI3-2)	-0.73 eV/atom
Ti₂I₄, (2TiI2-1)	-0.72 eV/atom
TiI₂, (1TiI2-1)	-0.68 eV/atom
TiI₂, (1TiI2-2)	-0.67 eV/atom
TiI₂, (1TiI2-3)	-0.45 eV/atom
I₂Ti₂, (2ITi-1)	-0.35 eV/atom
I₂Ti₂, (2ITi-2)	-0.10 eV/atom

Bulk crystals from OQMD123
I₁₂Ti₄	-0.81 eV/atom
I₈Ti₂	-0.74 eV/atom
I₄	0.00 eV/atom
Ti₃	0.00 eV/atom

C_ij (N/m)	xx	yy	xy
xx	61.01	12.60	-0.03
yy	12.57	60.90	-0.03
xy	0.00	0.00	48.89

Stiffness tensor eigenvalues
Eigenvalue 0	48.37 N/m
Eigenvalue 1	48.89 N/m
Eigenvalue 2	73.54 N/m

Property	Value
Minimum eigenvalue of Hessian [eV/Å²]	-0.00

D_VB (eV)	xx	yy	xy
Γ	0.58	0.62	-0.00
M	-0.59	0.37	-0.77
K	-2.30	-2.26	-0.01
k_VBM	-2.30	-2.26	-0.01

	xx	yy	xy
Band Gap	0.60	0.96	0.42

D_CB (eV)	xx	yy	xy
Γ	-3.47	-3.44	-0.01
M	-4.77	-4.30	-0.37
K	-4.56	-4.53	-0.01
k_CBM	-1.70	-1.29	0.42

Property (VBM)	Value
Min eff. mass	0.49 m₀
Max eff. mass	0.49 m₀
DOS eff. mass	0.49 m₀
Crystal coordinates	[-0.333, -0.333]
Warping parameter	-0.000
Barrier height	> 92.0 meV
Distance to barrier	> 0.0191 Å^-1

Property (CBM)	Value
Min eff. mass	1.03 m₀
Max eff. mass	1.52 m₀
DOS eff. mass	1.23 m₀
Crystal coordinates	[0.144, 0.144]
Warping parameter	0.009
Barrier height	> 31.6 meV
Distance to barrier	> 0.0191 Å^-1

Property	Value
KVP: Band gap (HSE06) [eV]	0.83
KVP: Direct band gap (HSE06) [eV]	0.83
Valence band maximum wrt. vacuum level (HSE06)	-3.23 eV
Conduction band minimum wrt. vacuum level (HSE06)	-2.40 eV

Property	Value
Band gap (G₀W₀) [eV]	1.09
Direct band gap (G₀W₀) [eV]	1.33
Valence band maximum wrt. vacuum level (G₀W₀)	-3.61 eV
Conduction band minimum wrt. vacuum level (G₀W₀)	-2.52 eV

Z^Ti_ij	u_x	u_y	u_z
P_x	-0.38	-0.00	0.00
P_y	-0.00	-0.38	-0.00
P_z	0.00	-0.00	0.16

Z^I_ij	u_x	u_y	u_z
P_x	0.19	0.00	-0.00
P_y	0.00	0.19	0.00
P_z	-0.00	-0.00	-0.08

Z^I_ij	u_x	u_y	u_z
P_x	0.19	0.00	0.00
P_y	0.00	0.19	-0.00
P_z	0.00	0.00	-0.08

Element	Relations
yyy	yyy=-xxy=-yxx=-xyx
Others	0=xxx=xxz=xyy=xyz=xzx=xzy=xzz=yxy=yxz=yyx=yyz=yzx= yzy=yzz=zxx=zxy=zxz=zyx=zyy=zyz=zzx=zzy=zzz

Properties
Static interband polarizability at (x) [Å]	10.021
Static interband polarizability at (y) [Å]	10.021
Static interband polarizability at (z) [Å]	0.442
Plasma frequency (x) [Å^0.5]	0.000
Plasma frequency (y) [Å^0.5]	0.000

Static polarizability	[Å]
Phonons only (x)	0.02
Phonons only (y)	0.02
Phonons only (z)	0.00
Total (phonons + electrons) (x)	10.05
Total (phonons + electrons) (y)	10.04
Total (phonons + electrons) (z)	0.44

Mode	Frequency (1/cm)	Degeneracy
Mode 1	0.1	3
Mode 2	85.2	2
Mode 3	133.7	1
Mode 4	221.8	2
Mode 5	276.3	1

Property	Value
The exciton binding energy from the Bethe–Salpeter equation (BSE) [eV].	0.44

#	Chemical symbol	Charges [\|e\|]
0	Ti	1.19
1	I	-0.59
2	I	-0.60

c_ij (e/Å^dim-1)	xx	yy	xy
x	0.00	0.00	-0.09
y	-0.09	0.09	0.00
z	-0.00	0.00	0.00

c^clamped_ij (e/Å^dim-1)	xx	yy	xy
x	0.00	0.00	-0.07
y	-0.07	0.07	0.00
z	0.00	0.00	0.00

Element	Relations
yyy	yyy=-xyx=-yxx=-xxy
Others	0=xxx=xxz=xyy=xyz=xzx=xzy=xzz=yxy=yxz=yyx=yyz=yzx= yzy=yzz=zxx=zxy=zxz=zyx=zyy=zyz=zzx=zzy=zzz

Miscellaneous details
Unique ID	1TiI2-2
Number of atoms	3
Number of species	2
Formula	TiI₂
Reduced formula	TiI₂
Stoichiometry	AB₂
Unit cell area [Å²]	12.302
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/TiI2/TiI2-088e8488f895
Old uid	TiI2-088e8488f895
Inversion symmetry	No
Layer group	p-6m2
Layer group number	78
Structure origin	original03-18
Band gap [eV]	0.596
gap_dir	0.616
gap_dir_nosoc	0.673
Vacuum level [eV]	4.024
Fermi level [eV]	0.695
minhessianeig	-0.000
Dynamically stable	Yes
Band gap (HSE06) [eV]	0.828
gap_dir_hse	0.828
vbm_hse	0.793
cbm_hse	1.622

Miscellaneous details
Band gap (G₀W₀) [eV]	1.090
gap_dir_gw	1.331
vbm_gw	0.418
cbm_gw	1.508
E_B	0.444
Static interband polarizability at (x) [Å]	10.021
Static interband polarizability at (y) [Å]	10.021
Static interband polarizability at (z) [Å]	0.442
Static polarizability (phonons) (x) [Å]	0.024
Static polarizability (phonons + electrons) (x) [Å]	10.045
Static polarizability (phonons) (y) [Å]	0.023
Static polarizability (phonons + electrons) (y) [Å]	10.045
Static polarizability (phonons) (z) [Å]	0.003
Static polarizability (phonons + electrons) (z) [Å]	0.444
Plasma frequency (x) [Å^0.5]	0.000
Plasma frequency (y) [Å^0.5]	0.000
Energy [eV]	-11.655
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]	0.052
Heat of formation [eV/atom]	-0.670

Atoms: TiI2

Convex hull

Stiffness tensor

Phonons

Deformation potentials

Band structure and DOS

Effective masses

Electronic band structure (HSE06@PBE)

Electronic band structure (G₀W₀@PBE)

Born charges

Second harmonic generation

Optical polarizability

Infrared polarizability

Raman spectrum

Optical absorption (BSE and RPA)

Bader charges

Piezoelectric tensor

Shift current

Miscellaneous