# Tag Info

Accepted

### How to understand the time-reversal symmetry in graphene?

Two-band model for graphene. To simplify the discussion of Dirac points, it is sufficient to consider a nearest-neighbor tight-binding 2-band model for graphene. This is a spinless model because spin-...
• 11.1k
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### Easy ways to generate "teaching" band structures in Python?

I'd suggest having a look at PythTB by Sinisa Coh and David Vanderbilt, which I found very useful and easy to use. Here's a stab at recreating the band structure of the 2d square lattice shown above <...
• 2,669

### Derivation of Slater-Koster equations

Spherical harmonics are not themselves full atomic orbitals. Consider the Hydrogen wave function, which separates into a radial part and an angular part. The latter is a spherical harmonic, but the ...
• 4,751

### DFT vs tight-binding solutions for a Dirac cone in graphene: Why is the DFT version squeezed?

Oh! I found the answer already. Since I'm doing the calculation along the High symmetry point. Im doing the calculation along G -> K -> M -> G, that's why the right hand sides show such phenomena. In ...
• 2,903
Accepted

### How to construct a Tight-Binding Hamiltonian from first-principles computations?

Yes! It is definitely possible and it is useful for calculating other things like electronic transport and first-principles values of Hubbard U (i.e. the ACBN0 method, which I have used a bit). Some ...
• 3,181
Accepted

### How to use wavefunctions/density to determine which orbitals lead to edge states?

One way of determining this is using the projected density of states (P-DOS) This resolves the DOS into specific orbitals thereby allowing you to discretize each orbitals weight for a specific energy. ...
• 3,699
Accepted

### Which software is suitable for visualizing the electron wavefunctions in a crystal?

The sisl python package might be useful to you. It has: Tools to build hamiltonians with user-defined basis orbitals. A very high level API to visualize the most ...
• 541
Accepted

### Software recommendations to construct band structures using tight binding

The sisl package can do exactly what you need. It should be easily extendible if you need some routines not implemented. There is also some tutorials, which has a focus on transport using the NEGF ...
• 3,699

### Easy ways to generate "teaching" band structures in Python?

Another package (sisl) can do the same thing, but a bit more verbose and dynamic. (disclaimer, I am the author). One of sisl's main goal is to interact with large TB models, and thus the complexity of ...
• 3,699

### Data format of wannier90_hr.dat from wannier90

The following code is a python function to read the wannier90_hr.dat, from which you should figure out its data structure. ...
• 15.2k

### Tools for working with tight-binding models

The sisl Python package can deal with Hamiltonians (and other physical matrices) in orthogonal and non-orthogonal basis sets. A simple example for graphene would be something like: ...
• 3,699

• 11.1k

### Evaluating Seebeck coefficient using DFT

I'm posting this here as an answer so that if anyone else runs into the same problem, they can get it clarified. After searching endlessly (because the SIESTA to BoltzTraP2 interface provided by the ...
• 2,653

### Data format of wannier90_hr.dat from wannier90

You can read the wanniertools code. In wanniertools, to calculate surface state, they write a surfstate subroutine in surfstate.f90 file. The slab Hamiltonian is restructured from a bulk Hamiltonian ...
• 391
Accepted

### How to determine the concrete value for the wavenumber in tight-binding approximation

It depends what you are trying to calculate. The possible k points that you care about are those in the first Brillouin zone. You can find a definition of that in a solid state physics textbook. In 1D ...
• 1,141
Accepted

### Calculating the surface state with Wannier tools

Wannier90 might not be good at preserving the symmetry. But they probably include a few new methods to enforce symmetry in Wannier90.v.3.1.0. Maybe you can check this. http://www.wannier.org/features/ ...
• 675

### Tight-binding computer program with electron thermodynamics

Probably what you want is something like 'density functional tight binding' (DFTB). The total energy, free energy, etc. contain contributions from the Hartree potential, XC, ion-ion interactions, etc.,...
• 1,573
Accepted

### Tight binding packages for Fermi velocity of slabs

I had more of a look and yeah, none of the available packages do this to my knowledge so I just wrote my own code. It isn't particularly hard, more just tedious efficiently figuring out where in your ...
• 321
1 vote

### How to get the crystal/ligand field splitting of d orbital of Fe complex using Quantum Espresso

You should take into account that for this type of square planar complex the set of 5 "d" orbilals of the iron atom are the ones that must be considered for the calculation. Usually, ...
• 11
1 vote

### Is it possible to construct a tight binding matrix of high atomic layer thin film from the lower one?

Just to preserve ProfM's comments that seem to to answer the question: In principle yes, but its accuracy will depend somehow on the specific features of your current TB model and what you want for ...

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