Atoms: HfI₂

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

Stability
Energy above convex hull [eV/atom]	0.114
Heat of formation [eV/atom]	-0.674
Dynamically stable	Yes

Basic properties
Magnetic state	NM
Band gap [eV]	0.630
Band gap (HSE06) [eV]	1.022
Band gap (G₀W₀) [eV]	1.421

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	3.773	-0.000	0.000	Yes
2	-1.887	3.268	0.000	Yes
3	0.000	0.000	18.895	No

Lengths [Å]	3.773	3.773	18.895
Angles [°]	90.000	90.000	120.000

Convex hull

HfI2 (1HfI2-1)
Heat of formation [eV/atom]	-0.67
Energy above convex hull [eV/atom]	0.11

Monolayers from C2DB
Hf2I6, (2HfI3-1)	-0.78 eV/atom
Hf2I6, (2HfI3-2)	-0.74 eV/atom
Hf2I4, (2HfI2-1)	-0.73 eV/atom
HfI2, (1HfI2-1)	-0.67 eV/atom
HfI2, (1HfI2-2)	-0.55 eV/atom
Hf2I2, (2HfI-1)	-0.42 eV/atom
HfI2, (1HfI2-3)	-0.20 eV/atom
Hf2I2, (2HfI-2)	-0.16 eV/atom

Bulk crystals from OQMD123
Hf4I16	-0.93 eV/atom
Hf2I6	-0.89 eV/atom
Hf2	0.00 eV/atom
I4	0.00 eV/atom

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	65.63	10.88	0.00
yy	10.65	66.37	0.00
xy	0.00	0.00	55.52

Stiffness tensor eigenvalues
Eigenvalue 0	55.23 N/m
Eigenvalue 1	55.52 N/m
Eigenvalue 2	76.77 N/m

Phonons

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

Deformation potentials

DVB (eV)	xx	yy	xy
Γ	4.11	4.03	0.03
M	0.16	1.80	-1.37
K	-0.26	-0.28	0.03
kVBM	-0.26	-0.28	0.03

	xx	yy	xy
Band Gap	1.57	1.53	-0.21

DCB (eV)	xx	yy	xy
Γ	-1.92	-2.15	0.02
M	1.79	0.36	1.18
K	-3.16	-3.20	0.02
kCBM	1.31	1.25	-0.19

Band structure and DOS

Effective masses

Property (VBM)	Value
Min eff. mass	0.28 m0
Max eff. mass	0.28 m0
DOS eff. mass	0.28 m0
Crystal coordinates	[0.333, 0.333]
Warping parameter	-0.000
Barrier height	> 158.7 meV
Distance to barrier	> 0.0191 Å-1

Property (CBM)	Value
Min eff. mass	0.49 m0
Max eff. mass	0.78 m0
DOS eff. mass	0.62 m0
Crystal coordinates	[0.149, 0.149]
Warping parameter	0.000
Barrier height	> 61.5 meV
Distance to barrier	> 0.0191 Å-1

Electronic band structure (HSE06@PBE)

Property	Value
KVP: Band gap (HSE06) [eV]	1.02
KVP: Direct band gap (HSE06) [eV]	1.77
Valence band maximum wrt. vacuum level (HSE06)	-3.17 eV
Conduction band minimum wrt. vacuum level (HSE06)	-2.15 eV

Electronic band structure (G₀W₀@PBE)

Property	Value
Band gap (G₀W₀) [eV]	1.42
Direct band gap (G₀W₀) [eV]	2.11
Valence band maximum wrt. vacuum level (G₀W₀)	-3.62 eV
Conduction band minimum wrt. vacuum level (G₀W₀)	-2.20 eV

Born charges

ZHfij	ux	uy	uz
Px	0.37	0.00	-0.00
Py	-0.00	0.37	0.00
Pz	-0.00	0.00	0.16

ZIij	ux	uy	uz
Px	-0.19	0.00	-0.00
Py	0.00	-0.19	0.00
Pz	0.00	-0.00	-0.08

ZIij	ux	uy	uz
Px	-0.19	0.00	0.00
Py	0.00	-0.19	-0.00
Pz	-0.00	0.00	-0.08

Second harmonic generation

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

Optical polarizability

Properties
Static interband polarizability at (x) [Å]	6.785
Static interband polarizability at (y) [Å]	6.785
Static interband polarizability at (z) [Å]	0.460
Plasma frequency (x) [Å0.5]	0.000
Plasma frequency (y) [Å0.5]	0.000

Infrared polarizability

Static polarizability	[Å]
Phonons only (x)	0.02
Phonons only (y)	0.02
Phonons only (z)	0.00
Total (phonons + electrons) (x)	6.80
Total (phonons + electrons) (y)	6.80
Total (phonons + electrons) (z)	0.46

Raman spectrum

Mode	Frequency (1/cm)	Degeneracy
Mode 1	0.	3
Mode 2	92.9	2
Mode 3	124.6	1
Mode 4	144.4	2
Mode 5	189.9	1

Optical absorption (BSE and RPA)

Property	Value
The exciton binding energy from the Bethe–Salpeter equation (BSE) [eV].	0.57

Bader charges

#	Chemical symbol	Charges [|e|]
0	Hf	1.21
1	I	-0.61
2	I	-0.61

Piezoelectric tensor

cij (e/Ådim-1)	xx	yy	xy
x	-0.00	-0.00	-0.01
y	-0.01	0.01	0.00
z	-0.00	-0.00	-0.00

cclampedij (e/Ådim-1)	xx	yy	xy
x	-0.00	-0.00	-0.03
y	-0.03	0.03	-0.00
z	-0.00	-0.00	-0.00

Shift current

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

Miscellaneous details
Unique ID	1HfI2-1
Number of atoms	3
Number of species	2
Formula	HfI2
Reduced formula	HfI2
Stoichiometry	AB2
Unit cell area [Å2]	12.329
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/HfI2/HfI2-05a69240794c
Old uid	HfI2-05a69240794c
Inversion symmetry	No
Layer group	p-6m2
Layer group number	78
Structure origin	original03-18
Band gap [eV]	0.630
gap_dir	1.283
gap_dir_nosoc	1.414
Vacuum level [eV]	4.318
Fermi level [eV]	1.529
minhessianeig	-0.000
Dynamically stable	Yes
Band gap (HSE06) [eV]	1.022
gap_dir_hse	1.768
vbm_hse	1.147
cbm_hse	2.168

Miscellaneous details
Band gap (G₀W₀) [eV]	1.421
gap_dir_gw	2.108
vbm_gw	0.698
cbm_gw	2.118
E_B	0.571
Static interband polarizability at (x) [Å]	6.785
Static interband polarizability at (y) [Å]	6.785
Static interband polarizability at (z) [Å]	0.460
Static polarizability (phonons) (x) [Å]	0.020
Static polarizability (phonons + electrons) (x) [Å]	6.805
Static polarizability (phonons) (y) [Å]	0.020
Static polarizability (phonons + electrons) (y) [Å]	6.805
Static polarizability (phonons) (z) [Å]	0.002
Static polarizability (phonons + electrons) (z) [Å]	0.463
Plasma frequency (x) [Å0.5]	0.000
Plasma frequency (y) [Å0.5]	0.000
Energy [eV]	-12.486
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]	0.114
Heat of formation [eV/atom]	-0.674