test-typst/main.typ

@@ -101,7 +101,7 @@ We classified these phonons into two categories based on their polarities:
     where the polarity gives rise to observable effects in the Raman spectra.
 
 #figure(
-  image("/画图/声子不连续/main.svg"),
+  image("/画图/声子不连续/embed.svg"),
   caption: [
     (a) Phonon dispersion of 4H-SiC along the A–#sym.Gamma–K high-symmetry path.
       Gray lines represent negligible-polar phonon modes,
@@ -125,16 +125,31 @@ Phonons at the #sym.Gamma point were used
 This approximation is widely adopted and justified by the fact that,
   although the phonons participating in Raman processes are not these strictly located at the #sym.Gamma point,
   their dispersion near the #sym.Gamma point is continuous with vanishing derivatives,
-  and their wavevector is very small
-    (about 0.01 AA in this paper, which corresponds to only 2% of the smallest reciprocal lattice vector of 4H-SiC).
-  // TODO: 确认这个数值
+  and their wavevector is very small (about 0.01 nm#sub([-1]) in this paper,
+    which corresponds to only 1% of the smallest reciprocal lattice vector of 4H-SiC),
+  as shown by the orange dotted line in @phonon.
 Therefore, negligible-polar phonons involved in Raman processes
   have nearly indistinguishable properties from those at the #sym.Gamma point.
 
-// 4H-SiC 在 Gamma 有 21 个distinct phonons，其中极性较弱的有 18 个。这些模式对应于点群  $\mathrm{C_{6v}}$ 的 12 个表示（$\mathrm{3A_1+4B_1+3E_1+4E_2}$。
-// 对于非极性声子的拉曼散射，我们将使用 Gamma 点的声子模式来近似描述。
-// 这是因为，尽管拉曼实验中，起作用的声子并不严格在 Gamma 点；但这些声子模式的散射谱在 Gamma 附近是连续且导数为零，且起作用的声子离开 Gamma 点的距离也很小（对于 532 nm 的激光，离开 Gamma 点的距离小于 0.01 Å），它们的性质与 Gamma 点的声子模式区别不大。
+// 4H-SiC 在 Gamma 有 21 个distinct phonons。
+// 其中 18 个被归类为极性较弱的声子。这是因为，4H-SiC 的原胞中，4 个 Si 原子所带的有效电荷差别不大，四个 C 原子所带的有效电荷差别也不大。
+// 在这些声子模式中，原胞中的 2 个 Si 原子运动方向与另外 2 个 Si 原子相反，2 个 C 原子的运动方向与另外 2 个 C 原子相反，极性相互抵消。
+There are 21 distinct phonons at the #sym.Gamma point in 4H-SiC.
+Among them, 18 phonons are classified as negligible-polar phonons.
+This classification is based on the fact that
+  the four Si atoms in the primitive cell carry similar Born effective charges (BEC),
+  as do the four C atoms. // TODO: refer
+In these 18 modes, the vibrations of two Si atoms are approximately opposite to those of the other two Si atoms,
+  and similarly for the C atoms,
+  leading to cancellations of macroscopic polarity.
 
+These phonon modes correspond to twelve irreducible representations of the $\mathrm{C_{6v}}$ point group: $\mathrm{3A_1 + 4B_1 + 3E_1 + 4E_2}$.
+
+
+18 of them are classified as negligible-polar phonons,
+  since 
+
+// TODO: 列个表格
 
 
 //