diff --git a/src/12_band_structures_in_higher_dimensions.md b/src/12_band_structures_in_higher_dimensions.md index cbca532ff684d4e581409aedda5b7bd56600e4e4..78aef2e03679acc6ba98a4e275b665a2384fef9b 100644 --- a/src/12_band_structures_in_higher_dimensions.md +++ b/src/12_band_structures_in_higher_dimensions.md @@ -230,6 +230,6 @@ Suppose we have a square lattice with lattice constant $a$, with a periodic pote ??? hint This is analogous to the 1D case: the states that interact have $k$-vectors $(\pi/a,0)$ and $(-\pi/a,0)$; ($\psi_{+}\sim e^{i\pi x /a}$ ; $\psi_{-}\sim e^{-i\pi x /a}$). -2. Let's now study the more complicate case of state $\mathbf{q}=(\pi/a,\pi/a)$. How many $k$-points have the same energy? Which ones? +2. Let's now study the more complicated case of state $\mathbf{q}=(\pi/a,\pi/a)$. How many $k$-points have the same energy? Which ones? 3. Write down the nearly free electron model Hamiltonian near this point. 4. Find its eigenvalues. \ No newline at end of file