Overview: Al₂Se₅

Structure info
Layer group	c2/m11
Layer group number	18
Structure origin	Lyngby22_LDP

Stability
Energy above convex hull [eV/atom]	0.011
Heat of formation [eV/atom]	-0.601
Dynamically stable	No

Basic properties
Magnetic	No
Band gap (PBE) [eV]	1.475

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	3.806	0.000	0.000	Yes
2	-1.903	7.567	0.000	Yes
3	-0.000	-0.000	34.282	No

Lengths [Å]	3.806	7.803	34.282
Angles [°]	90.000	90.000	104.116

Crystal structure

Symmetries
2D Bravais type	Centered rectangular (oc)
Layer group number	18
Layer group	c2/m11
Space group number (bulk in AA-stacking)	12
Space group (bulk in AA-stacking)	C2/m
Point group	2/m
Inversion symmetry	Yes

Structure data
Formula	Se5Al2
Stoichiometry	A2B5
Number of atoms	7
Unit cell area [Å2]	28.800
Thickness [Å]	3.536

Stability

Convex hull

Al2Se5 (1Al2Se5-1)
Heat of formation [eV/atom]	-0.60
Energy above convex hull [eV/atom]	0.01

Monolayers from C2DB
Al8Se12 (4Al2Se3-1)	-0.86 eV/atom
Al4Se6 (2Al2Se3-1)	-0.84 eV/atom
Al4Se6 (2Al2Se3-2)	-0.83 eV/atom
Al4Se6 (2Al2Se3-3)	-0.81 eV/atom
Al2Se3 (1Al2Se3-1)	-0.79 eV/atom
Al6Se9 (3Al2Se3-1)	-0.77 eV/atom
Al2Se3 (1Al2Se3-2)	-0.77 eV/atom
Al3Se4 (1Al3Se4-1)	-0.72 eV/atom
Al2Se2 (2AlSe-1)	-0.72 eV/atom
Al2Se2 (2AlSe-2)	-0.71 eV/atom
Al2Se2 (2AlSe-3)	-0.69 eV/atom
Al2Se5, (1Al2Se5-1)	-0.60 eV/atom
Al2Se4 (2AlSe2-1)	-0.55 eV/atom
AlSe2 (1AlSe2-1)	-0.55 eV/atom
Al2Se2 (2AlSe-4)	-0.36 eV/atom
Al2Se4 (2AlSe2-2)	-0.31 eV/atom
Al2Se2 (2AlSe-5)	-0.14 eV/atom
AlSe4 (1AlSe4-1)	-0.13 eV/atom
Se2 (2Se-1)	0.21 eV/atom
Se2 (2Se-2)	0.29 eV/atom

Bulk crystals from OQMD123
Al4Se6	-0.84 eV/atom
Al	0.00 eV/atom
Se3	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.20

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	52.44	3.23	-0.00
yy	3.65	13.54	-0.01
xy	0.00	-0.00	22.24

Stiffness tensor eigenvalues
Eigenvalue 0	13.24 N/m
Eigenvalue 1	22.24 N/m
Eigenvalue 2	52.74 N/m

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	1.475
Direct band gap (PBE)	1.575
Valence band maximum wrt. vacuum (PBE)	-5.414
Conduction band minimum wrt. vacuum (PBE)	-3.939

Effective masses

Property (VBM)	Value
Min eff. mass	0.06 m0
Max eff. mass	0.22 m0
DOS eff. mass	0.12 m0
Crystal coordinates	[0.002, 0.499]
Warping parameter	-0.001
Barrier height	> 22.3 meV
Distance to barrier	> 0.0169 Å-1

Property (CBM)	Value
Min eff. mass	0.16 m0
Max eff. mass	6.34 m0
DOS eff. mass	1.00 m0
Crystal coordinates	[0.000, 0.082]
Warping parameter	0.000
Barrier height	0.7 meV
Distance to barrier	0.00818 Å-1

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Se	0.06
1	Al	2.09
2	Se	-0.71
3	Se	-0.71
4	Se	-1.41
5	Se	-1.41
6	Al	2.09

Miscellaneous

Miscellaneous details
Unique ID	1Al2Se5-1
Number of atoms	7
Number of species	2
Formula	Se5Al2
Reduced formula	Se5Al2
Stoichiometry	A2B5
Unit cell area [Å2]	28.800
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree_LDP/A2B5/Al2Se5/Al2Se5-c9675b8e0933
Old uid	Al2Se5-9ed603d5a8f3
Space group (bulk in AA-stacking)	C2/m
Space group number (bulk in AA-stacking)	12
Point group	2/m
Inversion symmetry	Yes
Layer group number	18
Layer group	c2/m11
2D Bravais type	Centered rectangular (oc)
Thickness [Å]	3.536
Structure origin	Lyngby22_LDP

Miscellaneous details
Band gap (PBE) [eV]	1.475
Direct band gap (PBE) [eV]	1.575
gap_dir_nosoc	1.613
Vacuum level [eV]	1.707
Fermi level wrt. vacuum (PBE) [eV]	-4.676
Valence band maximum wrt. vacuum (PBE) [eV]	-5.414
Conduction band minimum wrt. vacuum (PBE) [eV]	-3.939
minhessianeig	-0.196
Dynamically stable	No
Energy [eV]	-29.100
Magnetic	No
Total magnetic moment [μB]	0.000
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]	0.011
Heat of formation [eV/atom]	-0.601