Different phase colors for different transmission eigenchannels

[Jahanzaib]

I'm plotting transmission eigenchannels in QuantumATK using isosurfaces with the BlueRed colormap, where color shows Phase (radians). When I plot two different eigenchannels at the same energy, they show different color/phase patterns even though they're in the same spot on the molecule. Is this normal, or does it mean something is wrong with my setup? Also, if I just want to compare how "big" or "spread out" the two channels are (not their phase), should I be plotting something else instead, like the magnitude/amplitude?

[yuby]

Yes, it’s normal. Different transmission eigenchannels can have different phase/colour patterns even in the same molecular region.

BlueRed colour = phase → useful for seeing phase/interference, but not for comparing size.
Isosurface = magnitude/amplitude → this is what you want for comparing how spatially spread out the channels are.
Use the same isovalue for both channels when comparing their spatial extent.
For a quantitative comparison, use \(|\psi|^2\) or integrate the magnitude/density over particular regions/atoms.

So: same location + different colours ≠ something wrong.

[Jahanzaib]

Many thanks for your reply.

Is there any tip or recommended approach for adjusting the transmission eigenstate isovalue to clearly identify which orbitals contribute to the transmission spectrum? Or do we need to adjust the isovalue manually until we obtain a clear representation of the orbital contributions?