Electronic properties of 2D and 1D systems: Difference between revisions
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Prev:[[LabQSM#Module 3: Low dimensional structures (6h)]] | Prev:[[LabQSM#Module 3: Low dimensional structures (6h)]] | ||
==Input set up for a low dimensional system:== | ==Input set-up for a low dimensional system:== | ||
Now we want to deal with systems of reduced dimensionality, e.g. periodic in one or two dimension but isolated in the other directions. This is accomplished by: | Now we want to deal with systems of reduced dimensionality, e.g. periodic in one or two dimension but isolated in the other directions. This is accomplished by: | ||
Revision as of 08:58, 1 April 2021
Prev:LabQSM#Module 3: Low dimensional structures (6h)
Input set-up for a low dimensional system:
Now we want to deal with systems of reduced dimensionality, e.g. periodic in one or two dimension but isolated in the other directions. This is accomplished by:
- Isolating the system in the non-periodic dimension as seen in Electronic properties of isolated molecules, so inserting an amount of vacuum in the supercell.
- Sampling the Brillouin zone that now has reduced dimension:
In Quantum ESPRESSO one needs to set the following:
K_POINTS automatic
nk nk 1 0 0 0 # for Gamma sampling using complex wavefunctions
# deprecated, unless for testing or debugging
this will generate a 2D sampling. In brief: you will need large supercells because of the present of vacuum which reflects in a large number of plane waves and a converged sampling of the BZ. The combination of this two issues makes the calculations of 2D system rather cumbersome.