From 41bf93c60fba1f4a1cb5cc95a2a0b1594e280792 Mon Sep 17 00:00:00 2001 From: "T. van der Sar" <t.vandersar@tudelft.nl> Date: Fri, 20 Mar 2020 19:18:35 +0000 Subject: [PATCH] Update 11_nearly_free_electron_model.md - typo --- src/11_nearly_free_electron_model.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/11_nearly_free_electron_model.md b/src/11_nearly_free_electron_model.md index 4fd9cc84..6f8d3cde 100644 --- a/src/11_nearly_free_electron_model.md +++ b/src/11_nearly_free_electron_model.md @@ -39,11 +39,11 @@ In other words: any electron wave function in a crystal is a product of a period ### Extra remarks -The wave function $u_n(\mathbf{r})e^{i\mathbf{kr}}$ is called a **Bloch wave**. +The wave function $u_n(\mathbf{r})e^{i\mathbf{k} \cdot \mathbf{r}}$ is called a **Bloch wave**. The $u_n(\mathbf{r})$ part is some unknown function. To calculate it we need to solve the Schrödinger equation. It is hard in general, but there are two limits when $U$ is "weak" and $U$ is "large" that provide us with most intuition. -If we change $\mathbf{k}$ by a reciprocal lattice vector $\mathbf{k} \rightarrow \mathbf{k} + h\mathbf{b}_1 + k\mathbf{b}_2 + l\mathbf{b}_3$, and we change $u_n(\mathbf{r}) \rightarrow u_n(\mathbf{r})\exp\left[-h\mathbf{b}_1 - k\mathbf{b}_2 - l\mathbf{b}_3\right]$ (also periodic!), we obtain the same wave function. Therefore energies of all bands $E_n(\mathbf{k})$ are periodic in reciprocal space with the periodicity of the reciprocal lattice. +If we change $\mathbf{k}$ by a reciprocal lattice vector $\mathbf{k} \rightarrow \mathbf{k} + h\mathbf{b}_1 + k\mathbf{b}_2 + l\mathbf{b}_3$, and we change $u_n(\mathbf{r}) \rightarrow u_n(\mathbf{r})\exp\left[i(-h\mathbf{b}_1 - k\mathbf{b}_2 - l\mathbf{b}_3)\cdot \mathbf{r}\right]$ (also periodic!), we obtain the same wave function. Therefore energies of all bands $E_n(\mathbf{k})$ are periodic in reciprocal space with the periodicity of the reciprocal lattice. Bloch theorem is extremely similar to the ansatz we used in [1D](7_tight_binding.md), and to the description of the [X-ray scattering](10_xray.md). -- GitLab