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seminar:graphene

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--- seminar:graphene [2019/12/03 14:59] – 作成 kimi
+++ seminar:graphene [2019/12/05 09:20] – [原子の位置と種類] kimi
@@ 行 1: / 行 1: @@
 ====== 総合演習 ======
+グラフェンを例に、より詳しい計算の演習を行う。
+===== 計算の前に =====
+{{ :seminar:graphene.png.001.png?400 |}}
+===== プログラムの概要 =====
+<code python>
+a0 = 2.461 # Lattice constant of Graphene
+from math import sqrt
+c1 = ( a0*sqrt(3.0)/2.0, a0/2.0, 0.0)
+c2 = (-a0*sqrt(3.0)/2.0, a0/2.0, 0.0)
+c3 = (0.0, 0.0, a0*8.0)              # Height of 3D unit cell
+from ase import Atom
+atom1 = Atom('C', (1.0/3.0, 2.0/3.0, 0.5))
+atom2 = Atom('C', (2.0/3.0, 1.0/3.0, 0.5))
+from ase import Atoms
+box1 = Atoms([atom1, atom2], pbc = True)
+box1.set_cell([c1, c2, c3], scale_atoms = True)
+from ase.calculators.jacapo import Jacapo
+solver1 = Jacapo(nbands = 8, kpts = (2, 2, 1), pw = 150, dw = 150)
+box1.set_calculator(solver1)
+solver1.calculate()
+</code>
+===== 単位格子の設定 =====
+<code python>
+b0 = 1.42 # C-C bond length
+from math import sqrt
+a0 = b0*sqrt(3.0)
+ax = a0*sqrt(3.0)/2.0    # ax = b0*3.0/2.0
+ay = a0/2.0
+az = a0*8                # Height of 3D unit cell
+c1 = ( ax, ay, 0.0)
+c2 = (-ax, ay, 0.0)
+c3 = (0.0, 0.0, az)
+unit_cell = [c1, c2, c3] # Unit cell
+</code>
+===== 原子の位置と種類 =====
+<code python>
+v1 = (1.0/3.0, 2.0/3.0, 0.5)
+v2 = (2.0/3.0, 1.0/3.0, 0.5)
+positions = [v1, v2]
+from ase import Atom
+list_of_atoms = []
+for pos in positions:
+  atm = Atom('C', pos)
+  list_of_atoms.append(atm)
+# # list_of_atoms is a list of [atom1, atom2]
+</code>
+===== 計算パラメーターの設定 =====
+<code python>
+# -------------------------
+# Calculational conditions
+# -------------------------
+kwargs = {}
+kwargs['nbands'] = 8        # Number of Valence electrons
+kwargs['kpts'] = (2, 2, 1)  # k-point sampling in the 1st BZ
+kwargs['pw'] = 150          # Energy cutoff for wave functions
+kwargs['dw'] = 150          # Energy cutoff for charge density
+</code>
+===== 計算の実行 =====
+<code python>
+# ---------------------------
+# Common part of calculations
+# ---------------------------
+from ase import Atoms
+box1 = Atoms(list_of_atoms, pbc = True)
+box1.set_cell(unit_cell, scale_atoms = True)
+from ase.calculators.jacapo import Jacapo
+solver1 = Jacapo(**kwargs)
+box1.set_calculator(solver1)
+solver1.calculate()
+</code>
+===== 結果の出力 =====
+<code python>
+# ------------------
+# Output on screen
+# ------------------
+print box1.get_total_energy()
+</code>

seminar/graphene.txt · 最終更新: 2022/08/23 13:34 by 127.0.0.1