Questions tagged [model-hamiltonians]

Questions examining the various types of Hamiltonian models that are used in materials modeling.

9 questions with no upvoted or accepted answers
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How to find the projected Hamiltonian for lowest flat-band in general?

In [1], starting with the bosonic Hamiltonian (Eqn. 1) for the dice lattice model with half flux density (with Ahronov-Bohm phases incorporated), \begin{equation} H=-t\sum_{\langle j,\mu\rangle}(a^\...
9
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66 views

How to choose the values of J and spin parameters in a heterogeneous spin system?

In this work, graphene-based systems that are described by mixed spin-3/2 and spin-5/2 are studied using the ising-model. A diagram of the structure is shown bellow: The Hamiltonian used is: \begin{...
8
votes
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51 views

For which materials is the Bethe lattice a good model to compute the density of states of the conduction band?

The Bethe lattice is exactly solvable in the limit where each lattice site has an infinite number of nearest-neighbors. In this limit it yields a semi-circular density of states in the conduction band....
6
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70 views

Example of a standard/archetypal/simple 4-band gapped condensed matter model with analytic results?

I am looking to study Berry phase-like phenomena in a gapped 4-band material model. In particular, I want to numerically and analytically calculate the Abelian Berry curvature integral of each band ...
6
votes
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47 views

How to interpret WannierTools Python code that generates tight-binding model in the wannier90_hr.dat format?

I am getting myself acquainted with Wannier Tools. Wannier Tools requires two inputs, a wt.in file, and a .dat file. This .dat file should have the structure explained in the manual here. This file ...
5
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0answers
57 views

Wavefunction magnitudes being degenerate everywhere on parameter space even though energy degeneracies occur at isolated points?

Cross-posted here: https://physics.stackexchange.com/questions/635887/wavefunction-magnitudes-being-degenerate-everywhere-on-parameter-space-even-thou Consider the usual simple 2-level gapless ...
5
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0answers
136 views

How to use hp.x in Quantum ESPRESSO to calculate Hubbard parameter

I want to work with GGA +U on Quantum espresso to calculate the electronic properties of Ni Co co-doped ZnO system, but I can't figure out how to use the hp.x program for my system to calculate the ...
4
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27 views

What parameters are needed to calculate the Dzyaloshinskii-Moriya interaction (DMI) using VASP?

I want to calculate the Dzyaloshinskii-Moriya interaction (DMI) at the interface of the Co/Pt structure. This Hamiltonian is written in the following form: \begin{align} H=D_{ij}(S_{i}\times{S_{j}}) \...