-    LORANDITE     -    TlAsS2

The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) starting from an experimental structure similar to the one reported in 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:  14  P2_1/c 
Lattice parameters (Å):  12.2960  11.3130  6.1140 
Angles (°):  90  104.21  90 

Symmetry (theoretical): 

Space group:  14  P2_1/c 
Lattice parameters (Å):  10.8057  10.8249  5.4543 
Angles (°):  90  103.48  90 

Cell contents: 

Number of atoms:  32 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Tl:  0.1022  0.3179  0.1891 
Tl:  0.1072  0.0652  0.6819 
As:  0.1414  0.7947  0.2223 
As:  0.1500  0.5794  0.6957 
S:  0.1494  0.3192  0.7121 
S:  0.1333  0.5787  0.2206 
S:  0.1305  0.7986  0.6708 
S:  0.1395  0.0654  0.1956 
Tl:  0.3978  0.8179  0.8109 
Tl:  0.3928  0.5652  0.3181 
As:  0.3586  0.2947  0.7777 
As:  0.3500  0.0794  0.3043 
S:  0.3506  0.8192  0.2879 
S:  0.3667  0.0787  0.7794 
S:  0.3695  0.2986  0.3292 
S:  0.3605  0.5654  0.8044 
Tl:  0.8978  0.6821  0.8109 
Tl:  0.8928  0.9348  0.3181 
As:  0.8586  0.2053  0.7777 
As:  0.8500  0.4206  0.3043 
S:  0.8506  0.6808  0.2879 
S:  0.8667  0.4213  0.7794 
S:  0.8695  0.2014  0.3292 
S:  0.8605  0.9346  0.8044 
Tl:  0.6022  0.1821  0.1891 
Tl:  0.6072  0.4348  0.6819 
As:  0.6414  0.7053  0.2223 
As:  0.6500  0.9206  0.6957 
S:  0.6494  0.1808  0.7121 
S:  0.6333  0.9213  0.2206 
S:  0.6305  0.7014  0.6708 
S:  0.6395  0.4346  0.1956 
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.
   

Dielectric Properties 


We define:

  • The Born effective charges, also called dynamical charges, are tensors that correspond to the energy derivative with respect to atomic displacements and electric fields or, equivalently, to the change in atomic force due to an electric field: The sum of the Born effective charges of all nuclei in one cell must vanish, element by element, along each of the three directions of the space.
  • The dielectric tensors are the energy derivative with respect to two electric fields. They also relate the induced polarization to the external electric field.

Born effective charges (Z): 

Tl: 1.9841 -0.0535 -0.5303 
-0.3627 10.7940 -4.4118 
4.0471 -8.5012 0.9651 
Eig. Value: 2.3803 14.0719 -2.7089 
Tl: 2.6353 -0.5851 0.0942 
-7.9260 27.8350 17.1051 
-7.7687 -8.1077 1.9363 
Eig. Value: -1.5757 29.4761 4.5062 
As: 4.6842 1.1992 -3.4374 
1.1666 28.5175 25.8108 
-7.9467 3.2587 7.8397 
Eig. Value: -3.5138 36.0949 8.4602 
As: 3.6225 0.2351 0.6857 
33.3538 -20.9093 43.8870 
-11.3915 11.8003 7.6415 
Eig. Value: 8.7915 -44.0998 25.6629 
S: -4.4950 -1.0254 -0.5041 
1.3652 25.9803 5.2929 
1.1003 8.8919 6.6669 
Eig. Value: -4.5029 28.3070 4.3482 
S: -2.8253 -0.6636 -1.9329 
11.1886 -10.7968 -47.9590 
1.1740 5.6785 -4.3772 
Eig. Value: -3.1018 -29.5012 14.6037 
S: -3.1378 0.8782 5.5490 
-25.5864 -10.8618 -16.2423 
6.5489 -5.1707 -15.1330 
Eig. Value: 10.9279 -15.4108 -24.6497 
S: -2.3313 2.0862 -0.2967 
88.1526 -35.7364 11.1303 
14.1100 8.2159 -4.7746 
Eig. Value: 32.4584 -67.4055 -7.8952 
Tl: 1.9176 0.0525 -0.5353 
0.3575 10.8065 4.4442 
4.1041 8.4579 0.9676 
Eig. Value: 2.3349 14.0790 -2.7221 
Tl: 2.6188 0.5572 0.1065 
7.9333 27.8257 -17.0545 
-7.7256 8.1030 1.9511 
Eig. Value: -1.5469 29.4538 4.4886 
As: 4.6117 -1.1575 -3.3556 
-1.3783 28.3361 -25.1306 
-7.7272 -3.2435 7.8477 
Eig. Value: -3.2801 35.6553 8.4203 
As: 3.6207 -0.2307 0.6806 
-33.7761 -21.0009 -43.9653 
-11.3255 -11.7549 7.6304 
Eig. Value: 8.8232 -44.2815 25.7086 
S: -4.5502 1.0404 -0.5148 
-1.5228 26.0263 -5.3561 
1.3357 -8.8877 6.7160 
Eig. Value: -4.5651 28.3727 4.3846 
S: -2.8198 0.6249 -1.9025 
-11.3373 -10.9116 47.8658 
1.1667 -5.6742 -4.3758 
Eig. Value: -3.0976 -29.5461 14.5365 
S: -3.0920 -0.8665 5.4183 
25.8041 -10.8036 16.1239 
6.5697 5.0808 -14.9544 
Eig. Value: 11.0136 -24.4967 -15.3669 
S: -2.4267 -2.1074 -0.3029 
-87.5679 -35.7882 -11.2898 
14.1346 -8.1554 -4.7935 
Eig. Value: 32.1591 -67.2142 -7.9533 
Tl: 1.4668 -0.0548 -0.5658 
18.6292 -5.0843 6.4442 
4.9592 -8.4649 1.0386 
Eig. Value: 8.2485 -11.9949 1.1676 
Tl: 1.7920 -0.5126 0.4840 
3.5495 -25.0073 -14.6274 
-6.2283 -8.3001 1.2580 
Eig. Value: -0.0530 -29.3125 7.4082 
As: 3.9017 1.4227 -3.2594 
42.5655 47.0227 -77.6975 
-6.5516 2.6838 7.7009 
Eig. Value: 0.6107 76.0794 -18.0648 
As: 1.9154 0.3093 -0.1240 
-17.1081 16.3448 -28.9722 
-8.0088 11.5495 9.1689 
Eig. Value: -5.8986 23.3971 9.9305 
S: -3.7068 -0.5067 -0.1419 
37.2976 -17.4509 24.9918 
-0.2462 7.8554 6.0664 
Eig. Value: 18.6676 -34.9501 1.1911 
S: -2.2848 -0.9065 -0.4670 
9.3843 -10.8286 7.5958 
0.0505 6.2577 -7.2822 
Eig. Value: 0.7028 -17.0464 -4.0520 
S: -2.1520 0.3049 4.5044 
-0.8339 1.7088 106.3267 
4.7130 -3.9285 -13.3223 
Eig. Value: -2.0752 46.1054 -57.7956 
S: -0.9750 1.4603 -0.0632 
-16.6638 -21.3453 -43.8582 
11.3975 9.4080 -5.3370 
Eig. Value: -6.8298 -32.7155 11.8880 
Tl: 1.4883 0.0611 -0.5624 
-18.5870 -5.1030 -6.4573 
4.9276 8.4875 1.0325 
Eig. Value: 8.2301 -11.9761 1.1637 
Tl: 1.7875 0.5298 0.4677 
-3.4881 -24.9721 14.5172 
-6.2934 8.3048 1.2286 
Eig. Value: -0.0923 -29.2493 7.3856 
As: 3.9391 -1.4235 -3.2737 
-42.6860 47.0758 77.7798 
-6.6802 -2.7510 7.5937 
Eig. Value: 0.5513 76.1492 -18.0921 
As: 1.9221 -0.3122 -0.1214 
17.0782 16.4502 28.9712 
-8.1266 -11.5841 9.1288 
Eig. Value: -5.9024 23.4331 9.9704 
S: -3.6924 0.4896 -0.1331 
-37.1451 -17.5266 -25.0943 
-0.3884 -7.8443 5.9740 
Eig. Value: 18.5618 -34.9995 1.1926 
S: -2.2805 0.9371 -0.4910 
-9.4873 -10.9119 -7.5031 
0.0078 -6.2466 -7.2204 
Eig. Value: 0.6760 -17.0550 -4.0338 
S: -2.1698 -0.3193 4.5619 
0.9589 1.7193 -106.4720 
4.6773 4.0055 -13.3566 
Eig. Value: -2.0831 46.1263 -57.8504 
S: -0.9684 -1.4633 -0.0368 
16.6720 -21.4042 43.8050 
11.3846 -9.4244 -5.4257 
Eig. Value: -6.8699 -32.7506 11.8222 
Atom type 

Dielectric tensors: 

 
Ɛ70.8561 2.0589 45.3388 
1.7291 12242.2706 0.0000 
46.3517 0.0000 1933.1419 
Eig. Value: 69.7279 12242.2709 1934.2698 
Refractive index (N): 8.4176 1.4349 6.7334 
1.3149 110.6448 0.0000 
6.8082 0.0000 43.9675 
Eig. Value: 8.3503 110.6448 43.9803 
Ɛ00.0000 0.0000 0.0000 
0.0000 0.0000 0.0000 
0.0000 0.0000 0.0000 
Eig. Value: 0.0000 0.0000 0.0000