Overview: Bi₄

Structure info
Layer group	pm2_1n
Layer group number	32
Structure origin	adhoc_material

Stability
Energy above convex hull [eV/atom]	0.096
Heat of formation [eV/atom]	0.096
Dynamically stable	Yes

Basic properties
Magnetic	No
Band gap [eV]	0.151
Band gap (HSE06) [eV]	0.346

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	4.574	-0.001	0.000	Yes
2	-0.001	4.862	0.000	Yes
3	0.000	0.000	17.110	No

Lengths [Å]	4.574	4.862	17.110
Angles [°]	90.000	90.000	90.032

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	32
Layer group	pm2_1n
Space group number (bulk in AA-stacking)	31
Space group (bulk in AA-stacking)	Pmn2_1
Point group	mm2
Inversion symmetry	No

Structure data
Formula	Bi4
Stoichiometry	A
Number of atoms	4
Unit cell area [Å2]	22.238
Thickness [Å]	3.481

Stability

Convex hull

Bi4 (4Bi-1)
Heat of formation [eV/atom]	0.10
Energy above convex hull [eV/atom]	0.10

Monolayers from C2DB
Bi4, (4Bi-1)	0.10 eV/atom
Bi2 (2Bi-1)	0.10 eV/atom
Bi4 (4Bi-2)	0.10 eV/atom

Bulk crystals from OQMD123
Bi2	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Deformation potentials

DVB [eV]	xx	yy	xy
Γ	0.29	1.21	0.01
Y	-6.79	-0.67	0.01
H	1.26	2.46	-0.03
C	-0.01	-5.78	0.02
H1	1.26	2.46	-0.03
X	1.26	2.46	-0.03
kVBM	-2.86	0.07	-0.01

	xx	yy	xy
Band gap [eV]	3.23	-1.48	-0.01

DCB [eV]	xx	yy	xy
Γ	-2.89	-2.30	-0.01
Y	-4.24	0.97	0.01
H	-0.95	-2.06	0.05
C	2.74	-0.17	-0.04
H1	-0.95	-2.06	0.05
X	-0.95	-2.06	0.05
kCBM	0.37	-1.42	-0.02

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	38.05	11.12	0.32
yy	10.27	17.78	0.40
xy	0.10	-0.32	23.83

Stiffness tensor eigenvalues
Eigenvalue 0	13.19 N/m
Eigenvalue 1	23.82 N/m
Eigenvalue 2	42.65 N/m

Piezoelectric tensor

cij [e/Å]	xx	yy	xy
x	0.00	0.00	0.29
y	-0.34	0.26	0.00
z	-0.00	-0.00	-0.00

cijclamped [e/Å]	xx	yy	xy
x	-0.00	0.00	-0.09
y	-0.32	0.30	-0.01
z	-0.00	0.00	0.00

Electronic bands

Band structure and DOS

Electronic band structure (HSE06@PBE)

Details
Band gap (HSE06) [eV]	0.346
Direct band gap (HSE06) [eV]	0.522
Valence band maximum wrt. vacuum level (HSE06) [eV]	-3.891
Conduction band minimum vs. vacuum (HSE06) [eV]	-3.544

Effective masses

Property (VBM)	Value
Min eff. mass	0.07 m0
Max eff. mass	0.54 m0
DOS eff. mass	0.19 m0
Crystal coordinates	[-0.006, -0.273]
Warping parameter	-0.001
Barrier height	> 26.2 meV
Distance to barrier	> 0.0138 Å-1

Property (CBM)	Value
Min eff. mass	0.06 m0
Max eff. mass	0.19 m0
DOS eff. mass	0.11 m0
Crystal coordinates	[0.188, 0.000]
Warping parameter	0.001
Barrier height	> 93.6 meV
Distance to barrier	> 0.0137 Å-1

Electronic properties

Born charges

ZBiij	ux	uy	uz
Px	1.47	0.02	0.01
Py	0.02	0.72	1.17
Pz	-0.00	0.04	-0.02

ZBiij	ux	uy	uz
Px	1.47	-0.01	-0.00
Py	0.00	0.72	-1.17
Pz	-0.00	-0.05	-0.02

ZBiij	ux	uy	uz
Px	-1.47	0.01	0.02
Py	0.01	-0.72	0.70
Pz	0.00	-0.01	0.02

ZBiij	ux	uy	uz
Px	-1.47	-0.03	-0.03
Py	-0.03	-0.72	-0.70
Pz	0.00	0.01	0.02

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Bi	0.04
1	Bi	-0.04
2	Bi	0.04
3	Bi	-0.04

Berry Phase Spectrum

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	187.131
Interband polarizability (y) [Å]	47.733
Interband polarizability (z) [Å]	0.490

Shift current

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

Miscellaneous

Miscellaneous details
Unique ID	4Bi-1
Number of atoms	4
Number of species	1
Formula	Bi4
Reduced formula	Bi
Stoichiometry	A
Unit cell area [Å2]	22.238
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/adhoc_materials/Bi4
Old uid	Bi4-4457ed5381e6
Space group (bulk in AA-stacking)	Pmn2_1
Space group number (bulk in AA-stacking)	31
Point group	mm2
Inversion symmetry	No
Layer group number	32
Layer group	pm2_1n
2D Bravais type	Rectangular (op)
Thickness [Å]	3.481
Structure origin	adhoc_material
Band gap [eV]	0.151
gap_dir	0.186
gap_dir_nosoc	0.308

Miscellaneous details
Vacuum level [eV]	3.658
Fermi level [eV]	-0.082
minhessianeig	-0.000
Dynamically stable	Yes
Band gap (HSE06) [eV]	0.346
Direct band gap (HSE06) [eV]	0.522
Valence band maximum wrt. vacuum level (HSE06) [eV]	-3.891
Conduction band minimum vs. vacuum (HSE06) [eV]	-3.544
Interband polarizability (x) [Å]	187.131
Interband polarizability (y) [Å]	47.733
Interband polarizability (z) [Å]	0.490
Energy [eV]	-18.315
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
topology	Not checked!
Energy above convex hull [eV/atom]	0.096
Heat of formation [eV/atom]	0.096