Collinear spin polarized Transiesta calculation

Asked by Sandra Rodriguez on 2020-01-22

I am trying to calculate the transmission function for a single molecule junction, where the molecule is a biradical (with singlet open shell or/and triplet ground state).

First, I carried out a geometry optimization of the junction with siesta, by means of a collinear spin polarized calculation:
SpinPolarized .true.
Spin.Total 0
Spin.Fix .true. #true can ve only used for colinear spin polarized calculations
%block DM.InitSpin
  134 +
  142 +
%endblock DM.InitSpin

Then, when I try to perform the Transiesta calculation, I got the nex error for both electrodes:
ERROR: Electrode: Left Electrode, nspin = 1 transiesta, nspin = 2
ERROR: Electrode: Right Electrode, nspin = 1 transiesta, nspin = 2

I can not impose spin on the electrodes, because the spin are on the molecule.

Is there any way to solve this?

Thanks in advance

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Solved by:
Sandra Rodriguez
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Nick Papior (nickpapior) said : #1


even though there is no spin-polarization for the electrode, you still have to do the calculation with collinear spin.

Also, it probably won't work with fix-spin. So you can do a Siesta calculation with fixed spin, but then to do transiesta you most likely need to remove the fixed spin, and use the DM file as a restart. Then *hope* your fixed spin won't be ruined.

Sandra Rodriguez (sandrarg) said : #3

Thanks a lot for the advice. Now transiesta calculation works!