Subtracting the three acoustic phonon branches from the six displacement normal modes leaves
(1)
At small wavevector, these involve relative motion of the two atomic basis sites rather than a rigid translation of the primitive unit cell. Their angular frequencies remain nonzero at the zone centre. The count uses the primitive unit cell; using all eight chemical atoms in the conventional unit cell would spuriously multiply the number of distinct branches in the first Brillouin zone.

Ancestors (13)

  1. ii
  2. c
  3. 2
  4. 2021
  5. Past exam of the condensed matter physics course of the University of Oxford
  6. Condensed matter physics course of the University of Oxford
  7. Year 3 of the physics course of the University of Oxford
  8. Physics course of the University of Oxford
  9. Undergraduate course of the University of Oxford
  10. Course of the University of Oxford
  11. University of Oxford
  12. List of universities
  13. Home

View article source

Discussion (0)

New discussion

There are no discussions about this article yet.

Articles by others on the same topic (0)

There are currently no matching articles.
See all articles in the same topic Create my own version