[Pw_forum] How can I extract hopping parameters from the output of wannier90

[Pang Rui]

Dear Giovanni
Thanks for your patient reply. Under your hint, I found a paper which
proofed the off diagonal elements had to be real under  T-symmetry. So I
think maybe some parameters I used need to be modified.
I meant the Hamiltionian in real space. I read the following two papers
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.81.245108
http://www.pnas.org/content/108/46/18622
There they seemed to use off diagonal elements directly as hopping
parameters.
I just simply added hr_plot=true in examples in PP and Wannier90. Nonzero
imaginary parts appeared in some examples like Si and diamond. Maybe they
are not well convergened.
As you suggest, I will post further questions on Wannier list if I have.

Best wishes
Pang Rui

On Sun, 12 Oct 2014 21:54:11 +0000, Giovanni Pizzi
<giovanni.pizzi at epfl.ch>
wrote:
> Dear Pang,
> just a comment on my previous message: I was thinking to the Hamiltonian
> in k space, but actually reading more carefully your message, I think
you
> meant the Hamiltonian in real space.
> 
> In which system do you find imaginary components in the off-diagonal
> matrix elements between WF? Did you check if your Wannier functions were
> converged and real? Do you have spin-orbit in your Hamiltonian?
> 
> In case, we can continue this discussion on the Wannier mailing-list,
that
> I think is more suited to this topic.
> 
> Giovanni
> 
> 
> 
> On 12 Oct 2014, at 21:28, Giovanni Pizzi wrote:
> 
> While the Slater-Koster parameters are real, the Hamiltonian matrix
> elements are complex.
> You should study how to build a tight-binding Hamiltonian; one good
point
> to start is the original paper by Slater and Koster
> http://journals.aps.org/pr/abstract/10.1103/PhysRev.94.1498
> or you can check many solid-state books or any other resource on
> tight-binding.
> 
> Best,
> Giovanni
> 
> --
> Giovanni Pizzi
> Post-doctoral Research Scientist
> EPFL STI IMX THEOS
> MXC 340 (Bâtiment MXC)
> Station 12
> CH-1015 Lausanne (Switzerland)
> Phone: +41 21 69 31124
> 
> 
> 
> 
> 
> On 11 Oct 2014, at 14:35, Pang Rui wrote:
> 
> Dear all
> Wannier functions were used in many papers to construct a tight binding
> model. The off diaganalization matrix elements were interpreted as the
> hopping parameters. However, I found that in most of the times, these
> elements were complex numbers. How can I related these complex numbers
to
> real numbers to parameter a TB model?
> 
> Best wishes!
> Pang Rui
> --
> PostDoc
> Department of Physics, South University of Science and Technology of
China
> Shenzhen, Guangdong, PRC, 518500
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-- 
PostDoc
Department of Physics, South University of Science and Technology of China
Shenzhen, Guangdong, PRC, 518500