Overview: TiSe₂

Structure info
Layer group	p-3m1
Layer group number	72
Structure origin	original03-18
COD id of parent bulk structure	COD 1010276
ICSD id of parent bulk structure	ICSD 31343

Stability
Energy above convex hull [eV/atom]	0.009
Heat of formation [eV/atom]	-1.122
Dynamically stable	No

Basic properties
Magnetic	No
Band gap (PBE) [eV]	0.000
Band gap (HSE06) [eV]	0.147

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	3.536	0.000	0.000	Yes
2	-1.768	3.062	0.000	Yes
3	0.000	-0.000	18.105	No

Lengths [Å]	3.536	3.536	18.105
Angles [°]	90.000	90.000	120.000

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	TiSe2
Stoichiometry	AB2
Number of atoms	3
Unit cell area [Å2]	10.829
Thickness [Å]	3.105

Stability

Convex hull

TiSe2 (1TiSe2-1)
Heat of formation [eV/atom]	-1.12
Energy above convex hull [eV/atom]	0.01

Monolayers from C2DB
Ti4Se8 (4TiSe2-1)	-1.13 eV/atom
Ti2Se3 (1Ti2Se3-1)	-1.12 eV/atom
TiSe2, (1TiSe2-1)	-1.12 eV/atom
TiSe2 (1TiSe2-2)	-1.00 eV/atom
Ti2Se2 (2SeTi-1)	-0.87 eV/atom
TiSe2 (1TiSe2-3)	-0.86 eV/atom
Ti2Se2 (2SeTi-2)	-0.83 eV/atom
Ti2Se6 (2TiSe3-1)	-0.83 eV/atom
Ti2Se2 (2SeTi-3)	-0.78 eV/atom
Ti2Se2 (2SeTi-4)	-0.56 eV/atom
Ti2Se2 (2SeTi-5)	-0.55 eV/atom
Se2 (2Se-1)	0.21 eV/atom
Se2 (2Se-2)	0.29 eV/atom

Bulk crystals from OQMD123
Ti6Se8	-1.22 eV/atom
Ti2Se4	-1.12 eV/atom
Ti5Se4	-1.06 eV/atom
Ti24Se12	-0.83 eV/atom
Se3	0.00 eV/atom
Ti3	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-1.72

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	59.15	10.79	0.10
yy	10.52	58.81	0.10
xy	0.00	0.00	45.81

Stiffness tensor eigenvalues
Eigenvalue 0	45.81 N/m
Eigenvalue 1	48.33 N/m
Eigenvalue 2	69.63 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)	-5.288

Electronic band structure (HSE06@PBE)

Key values [eV]
Band gap (HSE06)	0.147
Direct band gap (HSE06)	0.520
Valence band maximum wrt. vacuum (HSE06)	-4.741
Conduction band minimum wrt. vacuum (HSE06)	-4.594

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Ti	1.59
1	Se	-0.79
2	Se	-0.79

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	22.172
Interband polarizability (y) [Å]	22.172
Interband polarizability (z) [Å]	0.389
Plasma frequency (x) [eV Å0.5]	4.099
Plasma frequency (y) [eV Å0.5]	4.099

Miscellaneous

Miscellaneous details
Unique ID	1TiSe2-1
Number of atoms	3
Number of species	2
Formula	TiSe2
Reduced formula	TiSe2
Stoichiometry	AB2
Unit cell area [Å2]	10.829
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/TiSe2/TiSe2-320be81440f3
Old uid	TiSe2-320be81440f3
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]	3.105
Structure origin	original03-18
Band gap (PBE) [eV]	0.000
Direct band gap (PBE) [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	3.857

Miscellaneous details
Fermi level wrt. vacuum (PBE) [eV]	-5.288
minhessianeig	-1.720
Dynamically stable	No
Band gap (HSE06) [eV]	0.147
Direct band gap (HSE06) [eV]	0.520
Fermi level wrt. vacuum (HSE) [eV]	-4.709
Valence band maximum wrt. vacuum (HSE06) [eV]	-4.741
Conduction band minimum wrt. vacuum (HSE06) [eV]	-4.594
Interband polarizability (x) [Å]	22.172
Interband polarizability (y) [Å]	22.172
Interband polarizability (z) [Å]	0.389
Plasma frequency (x) [eV Å0.5]	4.099
Plasma frequency (y) [eV Å0.5]	4.099
Energy [eV]	-17.022
ICSD id of parent bulk structure	ICSD 31343
COD id of parent bulk structure	COD 1010276
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]	0.009
Heat of formation [eV/atom]	-1.122