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Electronic Band Structure of Monolayer MoS₂ Using the Tight-Binding Method

Overview

This repository provides a Python implementation for calculating and visualizing the electronic band structure of monolayer molybdenum disulfide (MoS₂) using the Slater–Koster Tight-Binding (TB) formalism. The implementation is developed in Jupyter Notebook and demonstrates the construction of the Tight-Binding Hamiltonian together with the numerical calculation of the energy dispersion along the high-symmetry path of the first Brillouin zone.

Monolayer MoS₂ is a representative transition metal dichalcogenide (TMD) with remarkable electronic and optical properties, including a direct band gap, strong spin–orbit coupling, and excellent potential for applications in nanoelectronics, optoelectronics, valleytronics, and photonics.


Physical Model

The electronic structure is described using an eleven-orbital Slater–Koster Tight-Binding model.

Each primitive unit cell contains:

  • One Molybdenum (Mo) atom
  • Two Sulfur (S) atoms

The Hamiltonian is constructed by considering:

  • Mo d-orbitals
  • S p-orbitals
  • Nearest-neighbor hopping interactions
  • Slater–Koster overlap parameters

The eigenvalue problem is solved for each k-point along the high-symmetry path (Γ–K–M–Γ) to obtain the electronic band structure.


Features

  • Python implementation of the Slater–Koster Tight-Binding model for monolayer MoS₂
  • Construction of the Hamiltonian matrix using orbital interactions
  • Implementation of Slater–Koster hopping parameters
  • Numerical diagonalization of the Hamiltonian
  • Calculation of electronic energy bands
  • Band structure visualization using Matplotlib
  • Well-documented Jupyter Notebook suitable for educational and research purposes

Slater–Koster Parameters

The implementation includes the following hopping integrals:

  • (V_{pp\pi})
  • (V_{pp\sigma})
  • (V_{pd\sigma})
  • (V_{pd\pi})
  • (V_{dd\sigma})
  • (V_{dd\pi})
  • (V_{dd\delta})

These parameters are used to construct the interaction matrices between Mo and S orbitals.


Repository Structure

band-structure-MoS2-2D
│
├── MoS2.ipynb          # Main notebook
├── README.md           # Project documentation
├── requirements.txt    # Python dependencies
├── figures/            # Generated figures
└── LICENSE

Requirements

The notebook requires the following Python packages:

  • numpy
  • matplotlib

Install the required packages using:

pip install -r requirements.txt

How to Run

  1. Clone the repository.
git clone https://github.com/your_username/band-structure-MoS2-2D.git
  1. Navigate to the project directory.
cd band-structure-MoS2-2D
  1. Launch Jupyter Notebook.
jupyter notebook
  1. Open MoS2.ipynb and execute the notebook cells sequentially.

Results

The notebook calculates the eigenvalues of the Tight-Binding Hamiltonian and plots the electronic band structure of monolayer MoS₂ along the high-symmetry path of the first Brillouin zone.

A typical output is shown below.

image

Applications

This project can be used for:

  • Tight-Binding model development
  • Electronic structure calculations
  • Two-dimensional materials research
  • Condensed matter physics education
  • Photonics and optoelectronic device studies
  • Validation of DFT and Quantum ESPRESSO calculations

References

  1. Liu, G.-B., Shan, W.-Y., Yao, Y., Yao, W., & Xiao, D. Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides.

  2. Cappelluti, E., Roldán, R., Silva-Guillén, J. Á., Ordejón, P., & Guinea, F. Tight-binding model and direct-gap/indirect-gap transition in single-layer and multilayer MoS₂.

  3. Ridolfi, E., et al. A tight-binding model for MoS₂ monolayers.


Future Improvements

Potential extensions of this project include:

  • Spin–Orbit Coupling (SOC)
  • Density of States (DOS)
  • Projected Density of States (PDOS)
  • Effective mass calculation
  • Berry curvature
  • Valley polarization
  • Comparison with Density Functional Theory (DFT)
  • Extension to other transition metal dichalcogenides (WS₂, MoSe₂, WSe₂)

License

This project is released under the MIT License.


Author

Shahnaz Mohammadi

image

About

Python implementation of the electronic band structure of monolayer MoS₂ using the Slater–Koster tight-binding model.

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