From 5d781ae1f32cf62dbacb5c1bf5df47319ac97f95 Mon Sep 17 00:00:00 2001
From: guanjihuan <34735497+guanjihuan@users.noreply.github.com>
Date: Mon, 9 Aug 2021 16:25:38 +0800
Subject: [PATCH] update

---
 .../flat_bands_of_kagome lattice.py           | 21 +++++
 ...flat_bands_of_kagome lattice_with_sympy.nb | 90 +++++++++++++++++++
 2 files changed, 111 insertions(+)
 create mode 100644 academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice.py
 create mode 100644 academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice_with_sympy.nb

diff --git a/academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice.py b/academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice.py
new file mode 100644
index 0000000..29ec15b
--- /dev/null
+++ b/academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice.py	
@@ -0,0 +1,21 @@
+import numpy as np
+from math import *
+import guan
+
+def hamiltonian(kx, ky):  # kagome lattice
+    k1 = kx
+    k2 = kx/2+ky*sqrt(3)/2
+    k3 = -kx/2+ky*sqrt(3)/2
+    h = np.zeros((3, 3), dtype=complex)
+    h[0, 1] = cos(k1)
+    h[0, 2] = cos(k2)
+    h[1, 2] = cos(k3)
+    h = h + h.transpose().conj()
+    t = 1
+    h = -2*t*h
+    return h
+
+kx_array = np.linspace(-pi ,pi, 100)
+ky_array = np.linspace(-pi ,pi, 100)
+eigenvalue_array = guan.calculate_eigenvalue_with_two_parameters(kx_array, ky_array, hamiltonian)
+guan.plot_3d_surface(kx_array, ky_array, eigenvalue_array, xlabel='kx', ylabel='ky', zlabel='E')
\ No newline at end of file
diff --git a/academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice_with_sympy.nb b/academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice_with_sympy.nb
new file mode 100644
index 0000000..742560a
--- /dev/null
+++ b/academic_codes/2021.08.09_flat_bands_of_kagome lattice/flat_bands_of_kagome lattice_with_sympy.nb	
@@ -0,0 +1,90 @@
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+
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+Notebook[{
+Cell[BoxData[{
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+ RowBox[{
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