dmitry-skachkov/g-tensor

Plot tensor in VESTA

Plot tensor in VESTA

• Examples
• How to plot
  • Calculate tensor principal axes
  • Add vectors in VESTA manually
  • Add vectors in VESTA automatically

Examples for plotting of EPR g- and A-tensors

Tensor can be plotted as double vectors for three principal axes of the tensor with vector lengths proportional to the tensor principal values.

Example 1. Zn_Ga2 defect structure in β-Ga₂O₃; spin density is indicated in yellow, g-tensor principal axes are indicated by thick double arrows with their length proportional to the Δg (deviation from the free electron value g_e = 2.002391), and green colored Ga atoms are the ones with strong superhyperfine (SHF) interaction. The small O spheres are color coded: red O(1), pink O(2), and orange O(3), and the polyhedra surrounding the Ga and their type are indicated. The thin double arrows show the principal axes of SHF interaction. Figure from

Example 2. V_Ga2 defect structure in β-Ga₂O₃, spin density, g-tensor, and Ga atoms with strong hyperfine interaction. From

How to plot

Calculate tensor principal axes

Program src/Diag1.f90 takes the tensor from Quantum Espresso output, calculates principal values of g-tensor (A-tensor), and calculates Miller indexes (u,v,w) of tensor principal axes:

 axis of g-tensor in lattice vector notations u,v,w (for plot in VESTA)
--------------------------------------------------------------------------------
     -0.0261296      0.0123988      0.0392910
      0.0261296     -0.0123988     -0.0392910
--------------------------------------------------------------------------------

Add vectors in VESTA manually

Edit -> Vectors and click "New"

Add vector in (u,v,w) coordinates, change radius (thickness of the vector), color, and uncheck "Penetrate atom"

Select atom and click "Set", change scale factor to 1

Add other vectors to the atom.
Tip: If you need to set vector between atoms, you can add additional atom at this point and set the size of the atom to 0.2.

Add vectors in VESTA automatically

In .xsf file with atom coordinates you can add six vectors to first six atoms (the vectors should be as units in crystollographic axes):

PRIMCOORD
  200    1                                               
  Ga     6.1068369711   1.5200228942   4.4761945299     -0.0261296      0.0123988      0.0392910  
  ...
  Ga     4.7167174875   1.5200228942   1.1556557386      0.0261296     -0.0123988     -0.0392910
  Ga    10.8217174641   0.0000000000   1.1556557386     

Edit file

Open .xsf file with VESTA and edit color, size,... of the vectors and rearrange them to one particular atom instead of six:

Edit -> Vectors