Scattering map

In examples/scattering_map.py we learn how to output the map of scattering processes. Let us set the parameters suitable for this demonstration and switch on the scattering map:

OUTPUT_FOLDER_NAME             = 'Scattering map in fishbone nanowire'
NUMBER_OF_PHONONS              = 300
T                              = 50.0
OUTPUT_SCATTERING_MAP          = True

SIDE_WALL_ROUGHNESS            = 2e-9
HOLE_ROUGHNESS                 = 2e-9
TOP_ROUGHNESS                  = 0.2e-9
BOTTOM_ROUGHNESS               = 0.2e-9

Note that it's to run for a limited number of phonons because otherwise the scattering will become huge and difficult to open. Below it the example of obtained scattering map.

Illustrations of phonon trajectories and coordinated of scattering events.

We can observe side walls mostly experience diffuse scattering, while top and bottom walls show mainly specular scattering because of the roughness we set above.

A more detailed example below from Ref. 1 shows how the scattering maps evolve as the temperature is increased. Specifically, we can see how lots of specular scattering events are present at 4 K, but at higher temperatures diffuse scattering becomes dominant at 50 K, and at 100 K internal scattering event become the visible as well.

Another example of phonon scattering maps.

Reference

1. Anufriev et al. Nanoscale, 11, 13407-13414 (2019)