Overview: YSe₂

Structure info
Layer group	p-4m2
Layer group number	59
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.489
Heat of formation [eV/atom]	-0.919
Dynamically stable	No

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

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	4.083	0.000	0.000	Yes
2	0.000	4.083	0.000	Yes
3	-0.000	0.000	19.384	No

Lengths [Å]	4.083	4.083	19.384
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Square (tp)
Layer group number	59
Layer group	p-4m2
Space group number (bulk in AA-stacking)	115
Space group (bulk in AA-stacking)	P-4m2
Point group	-42m
Inversion symmetry	No

Structure data
Formula	YSe2
Stoichiometry	AB2
Number of atoms	3
Unit cell area [Å2]	16.673
Thickness [Å]	3.604

Stability

Convex hull

YSe2 (1YSe2-1)
Heat of formation [eV/atom]	-0.92
Energy above convex hull [eV/atom]	0.49

Monolayers from C2DB
Y2Se6 (2YSe3-1)	-1.22 eV/atom
SeY (1SeY-1)	-1.08 eV/atom
YSe2, (1YSe2-1)	-0.92 eV/atom
Se2 (2Se-1)	0.21 eV/atom
Se2 (2Se-2)	0.29 eV/atom

Bulk crystals from OQMD123
SeY	-1.79 eV/atom
Se3	0.00 eV/atom
Y2	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-1.33

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	12.41	4.78	-0.00
yy	4.83	12.35	-0.00
xy	0.00	0.00	-6.25

Stiffness tensor eigenvalues
Eigenvalue 0	-6.25 N/m
Eigenvalue 1	7.57 N/m
Eigenvalue 2	17.18 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)	-6.654

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Y	1.77
1	Se	-0.89
2	Se	-0.89

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	18.516
Interband polarizability (y) [Å]	18.634
Interband polarizability (z) [Å]	0.394
Plasma frequency (x) [eV Å0.5]	5.308
Plasma frequency (y) [eV Å0.5]	5.325

Miscellaneous

Miscellaneous details
Unique ID	1YSe2-1
Number of atoms	3
Number of species	2
Formula	YSe2
Reduced formula	YSe2
Stoichiometry	AB2
Unit cell area [Å2]	16.673
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB2/YSe2/YSe2-a1f75ad3deac
Old uid	YSe2-a1f75ad3deac
Space group (bulk in AA-stacking)	P-4m2
Space group number (bulk in AA-stacking)	115
Point group	-42m
Inversion symmetry	No
Layer group number	59
Layer group	p-4m2
2D Bravais type	Square (tp)
Thickness [Å]	3.604
Structure origin	original03-18
Band gap (PBE) [eV]	0.000

Miscellaneous details
Direct band gap (PBE) [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	2.874
Fermi level wrt. vacuum (PBE) [eV]	-6.654
minhessianeig	-1.330
Dynamically stable	No
Interband polarizability (x) [Å]	18.516
Interband polarizability (y) [Å]	18.634
Interband polarizability (z) [Å]	0.394
Plasma frequency (x) [eV Å0.5]	5.308
Plasma frequency (y) [eV Å0.5]	5.325
Energy [eV]	-14.413
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]	0.489
Heat of formation [eV/atom]	-0.919