Solid State Physics in a Nutshell: Topic 5-2: Nyquist Frequency and Group Velocity

In this video we find the physically significant values of q, our wave vector. We then use our dispersion to find group and phase velocities. In addition, we define the Nyquist frequency in conjunction with our physically significant q values.

[@tomasgerasimidis482]

All the formalism with translation by 2pi/a was messing with my head and I couldn't see how a random geometric unit cell contained all the answers. "Wavelengths shorter than the atomic spacing carry no physical meaning" (paraphasing) is what gave me the "Uh huh!" moment. Thank you!

[@Plams5]

Yall are life savers!!

[@sayandebnath6445]

which one of them will be group velocity....well what do think?? Really?

[@sayandebnath6445]

what phonon? You didn't even introduce phonons!