The optical properties of 2D materials with the VASP code
Due to the enhanced coulomb interaction and the quantum confinement effect in the two-dimensional limit, the optical properties should be investigated with the GW+BSE method.
The practical calculation flow is the following :
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Perform a ground state DFT or HSE06 hybrid calculation.
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Based on previous converged charge density and wavefunction, increasing the number of unoccupied orbitals to generate new charge density and wavefunction.
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Preform a GW calculation (keeping orbitals fixed) and calculate the quasiparticle energies and screened Coulomb kernel. (Keep the Wxxx.tmp and WFULLxxx.tmp files).
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Perform BSE calculation (the dielectric function will be written in vasprun.xml)
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Plot the results using Sumo or OriginLab
I will soon upload an examples related to the optical properties of two-dimensional materials using DFT and then based on GW+BSE implemented in VASP package.