Overview: Te₂Ge₂

Structure info
Layer group	p4/mmm
Layer group number	61
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.469
Heat of formation [eV/atom]	0.375
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	5.745	-0.000	0.000	Yes
2	-0.000	5.745	0.000	Yes
3	0.000	0.000	15.000	No

Lengths [Å]	5.745	5.745	15.000
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Square (tp)
Layer group number	61
Layer group	p4/mmm
Space group number (bulk in AA-stacking)	123
Space group (bulk in AA-stacking)	P4/mmm
Point group	4/mmm
Inversion symmetry	Yes

Structure data
Formula	Te2Ge2
Stoichiometry	AB
Number of atoms	4
Unit cell area [Å2]	33.005
Thickness [Å]	0.000

Stability

Convex hull

Ge2Te2 (2GeTe-3)
Heat of formation [eV/atom]	0.38
Energy above convex hull [eV/atom]	0.47

Monolayers from C2DB
Te2Ge2 (2GeTe-1)	-0.04 eV/atom
TeGe (1GeTe-1)	-0.01 eV/atom
Te2Ge2 (2GeTe-2)	-0.00 eV/atom
Te2Ge (1GeTe2-1)	0.07 eV/atom
Te2Ge (1GeTe2-2)	0.08 eV/atom
Te4Ge2 (2GeTe2-1)	0.14 eV/atom
Te2 (2Te-1)	0.16 eV/atom
Te2Ge (1GeTe2-3)	0.20 eV/atom
Te4Ge2 (2GeTe2-2)	0.27 eV/atom
Te2 (2Te-2)	0.29 eV/atom
Te2Ge2, (2GeTe-3)	0.38 eV/atom
Ge2 (2Ge-1)	0.48 eV/atom
Ge2 (2Ge-2)	0.49 eV/atom

Bulk crystals from OQMD123
TeGe	-0.09 eV/atom
Ge2	0.00 eV/atom
Te3	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-3.11

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	-9.41	51.05	-0.00
yy	51.05	-9.41	-0.00
xy	0.00	0.00	-24.82

Stiffness tensor eigenvalues
Eigenvalue 0	-60.46 N/m
Eigenvalue 1	-24.82 N/m
Eigenvalue 2	41.64 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)	-4.464

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Ge	0.37
1	Ge	0.37
2	Te	-0.37
3	Te	-0.37

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	13.988
Interband polarizability (y) [Å]	13.988
Interband polarizability (z) [Å]	0.533
Plasma frequency (x) [eV Å0.5]	8.768
Plasma frequency (y) [eV Å0.5]	8.768

Miscellaneous

Miscellaneous details
Unique ID	2GeTe-3
Number of atoms	4
Number of species	2
Formula	Te2Ge2
Reduced formula	TeGe
Stoichiometry	AB
Unit cell area [Å2]	33.005
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB/GeTe/Ge2Te2-8ef318b354de
Old uid	Ge2Te2-8ef318b354de
Space group (bulk in AA-stacking)	P4/mmm
Space group number (bulk in AA-stacking)	123
Point group	4/mmm
Inversion symmetry	Yes
Layer group number	61
Layer group	p4/mmm
2D Bravais type	Square (tp)
Thickness [Å]	0.000
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]	2.348
Fermi level wrt. vacuum (PBE) [eV]	-4.464
minhessianeig	-3.106
Dynamically stable	No
Interband polarizability (x) [Å]	13.988
Interband polarizability (y) [Å]	13.988
Interband polarizability (z) [Å]	0.533
Plasma frequency (x) [eV Å0.5]	8.768
Plasma frequency (y) [eV Å0.5]	8.768
Energy [eV]	-13.941
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]	0.469
Heat of formation [eV/atom]	0.375