-    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: 
Number of atom types: 
Chemical composition: 

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: 

Size:

  
Nx:  Ny:  Nz:    
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.

Horizontal:
Xmin:
Xmax:
Vertical:
Ymin:
Ymax:
 
Choose the polarization of the lasers.
I ∥ 
I ⊥ 
I Total 

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 ⊥  I Total 
You can define the size of the supercell for the visualization of the vibration.
Nx: 
Ny: 
Nz: 
Normalized
Raw
Options for intensity.