Dear all,
See the attached figure from the literature. My question is how to read a phonon dispersion curve. From a standard textbook of solid physics, the x-axis should be a wave vector. Why here the x-axis is marked with several of peculiar symbols. A phonon dispersion curve should also indicate the wave propogation direction, but i find no such an specification. Are there any default directions for a dispersion curve?
Dear Mr. Qiao Li,
usually those symbols denote points (in the reciprocal space) of high symmetry (see for example https://en.wikipedia.org/wiki/Brillouin_zone#/media/File:Brillouin_Zone_(1st,_FCC).svg).
Without reading the actual paper from which the figure comes from, I can not tell you which points the author is referring to. What I can tell you is the meaning behind those symbols: Suppose you went from the point labelled Y to the point labelled A (in your attached figure). Those points refer to points in the reciprocal space, which is the space where waves "live in". Therefore, as you walk along the direction Y -> A, each "step" corresponds to a wavevector, i. e. each point contains the information about (1) the magnitude of the wavevector and (2) its direction, which you can imagine to be the direction of the vector connecting the origin of the reciprocal space and the point you are currently "standing on".
Some references:
Introduction to Solid State Physics, Charles Kittel: Chapter 4
Solid State Physics, Neil W. Ashcroft: Chapter 22
Solid State Physics, Giuseppe Grosso: Chapter 9
Hopefully, I could help you somehow :). Furthermore, I appreciate any feedback.
Kindly regards,
Giuseppe
Dear Mr. Qiao Li,
usually those symbols denote points (in the reciprocal space) of high symmetry (see for example https://en.wikipedia.org/wiki/Brillouin_zone#/media/File:Brillouin_Zone_(1st,_FCC).svg).
Without reading the actual paper from which the figure comes from, I can not tell you which points the author is referring to. What I can tell you is the meaning behind those symbols: Suppose you went from the point labelled Y to the point labelled A (in your attached figure). Those points refer to points in the reciprocal space, which is the space where waves "live in". Therefore, as you walk along the direction Y -> A, each "step" corresponds to a wavevector, i. e. each point contains the information about (1) the magnitude of the wavevector and (2) its direction, which you can imagine to be the direction of the vector connecting the origin of the reciprocal space and the point you are currently "standing on".
Some references:
Introduction to Solid State Physics, Charles Kittel: Chapter 4
Solid State Physics, Neil W. Ashcroft: Chapter 22
Solid State Physics, Giuseppe Grosso: Chapter 9
Hopefully, I could help you somehow :). Furthermore, I appreciate any feedback.
Kindly regards,
Giuseppe
- Badges
- Science topic
- Similar topics
- Vectorization