- #1

ianmgull

- 20

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This is a multi-part problem. I'm having trouble getting started. Any insights would be greatly appreciated.

Prompt:

To start off with, I think I'm finding the notation confusing. Specifically I'm not sure what U_200 refers to. Some thoughts:

I know that both the potential, and the periodic component of the bloch function can be expanded in a Fourier series in the nearly free electron model. I'm asumming that U_200 is the potential where k_x = 2 and k_y = k_z = 0, but the letter U is sometimes used for both potential and the periodic component of the block wavefunction so I'm a bit confused.

Secondly, since there are two waves with the same energy, does that imply that I'll need to use degenerate perturbation theory?

Thanks for the help. I'm not a condensed matter person and this class was supposed to be fun, but I'm struggling.

Prompt:

I know that both the potential, and the periodic component of the bloch function can be expanded in a Fourier series in the nearly free electron model. I'm asumming that U_200 is the potential where k_x = 2 and k_y = k_z = 0, but the letter U is sometimes used for both potential and the periodic component of the block wavefunction so I'm a bit confused.

Secondly, since there are two waves with the same energy, does that imply that I'll need to use degenerate perturbation theory?

Thanks for the help. I'm not a condensed matter person and this class was supposed to be fun, but I'm struggling.

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