- TELLURANTIMONY - Sb₂Te₃

Theoretical atomic positions and lattice parameters at experimental volum from AMCSD

Crystal Structure

Because of the translational symmetry all the calculations are performed in the primitive unit cell and not in the conventional unit cell. The following information regarding the structure is given with respect to this primitive unit cell, which sometimes can take an unintuitive shape.

Symmetry (experimental):

Space group:	166		R-3m
Lattice parameters (Å):	2.2564	2.2564		16.1177
Angles (°):	90.0	90.0		120.0

Symmetry (theoretical):

Space group:	166		R-3m
Lattice parameters (Å):	10.4755	10.4755		10.4755
Angles (°):	23.5	23.5		23.5

Cell contents:

Number of atoms:	5
Number of atom types:	2
Chemical composition:	0

Atomic positions (theoretical):

Bi:	0.3968	0.3968	0.3968
Te:	0.7851	0.7851	0.7851
Te:	0.0000	0.0000	0.0000
Bi:	0.6032	0.6032	0.6032
Te:	0.2149	0.2149	0.2149

Atom type

We have listed here the reduced coordinates of all the atoms in the primitive unit cell.
It is enough to know only the position of the atoms from the assymetrical unit cell and then use the symmetry to build the whole crystal structure.

Visualization of the crystal structure:

You can define the size of the supercell to be displayed in the jmol panel as integer translations along the three crystallographic axis.
Please note that the structure is represented using the primitive cell, and not the conventional one.

Powder Raman

Powder Raman spectrum

The intensity of the Raman peaks is computed within the density-functional perturbation theory. The intensity depends on the temperature (for now fixed at 300K), frequency of the input laser (for now fixed at 21834 cm^-1, frequency of the phonon mode and the Raman tensor. The Raman tensor represents the derivative of the dielectric tensor during the atomic displacement that corresponds to the phonon vibration. The Raman tensor is related to the polarizability of a specific phonon mode.

Choose the polarization of the lasers.

I ∥

I ⊥

I Total

Horizontal:

Xmin:
Xmax:

Vertical:

Ymin:
Ymax:

Data about the phonon modes

Frequency of the transverse (TO) and longitudinal (LO) phonon modes in the zone-center. The longitudinal modes are computed along the three cartesian directions. You can visualize the atomic displacement pattern corresponding to each phonon by clicking on the appropriate cell in the table below.

1	ac	0	0	0	0
2	ac	0	0	0	0
3	ac	0	0	0	0
4	Eg	46	46	46	46	4.052e+43 0.5	3.272e+43 0.4	7.324e+43 0.8
5	Eg	46	46	46	46	4.052e+43 0.5	5.468e+43 0.6	9.520e+43 1.1
6	A1g	60	60	60	60	7.527e+45 85.0	1.324e+45 15.0	8.851e+45 100.0
7	Eu	71	71	71	71
8	Eu	71	99	99	71
9	Eu	99	99	99	99
10	Eu	99	108	108	99
11	A2u	108	113	113	112
12	Eg	113	113	113	113	1.171e+45 13.2	1.975e+45 22.3	3.146e+45 35.5
13	Eg	113	132	132	113	1.171e+45 13.2	1.269e+45 14.3	2.440e+45 27.6
14	A2u	143	143	143	147
15	A1g	167	167	167	167	1.101e+45 12.4	4.530e+43 0.5	1.147e+45 13.0

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥