paper/main.tex

@@ -62,6 +62,19 @@ In this paper, we do some things. We do something for the first time.
 
 \subsection{Phonons in Perfect 4H-SiC}
 
+% 拉曼活性的声子模式对应于 Gamma 点附近的声子模式。
+% 根据这些声子模式在拉曼实验中的表现，我们将这些声子分成三个部分。
+
+Raman scattering peeks correspond to phonons located near $\Gamma$ point in reciprocal space.
+We classified these phonons into three categories according to their behavior in Raman scattering:
+  (1) phonons could not be observed in Raman scattering spectrum,
+    either because they are Raman inactive or their scattering intensity is too weak;
+  (2) phonons could be observed in Raman scattering spectrum and with weak or no polarities,
+    their frequencies were independent of the direction of the incident light;
+  (3) strong polar phonons,
+    which were visible in Raman scattering spectrum,
+    and their frequencies depend on the direction of the incident light.
+
 % 我们计算了 4H-SiC 在 A-Gamma 和 Gamma-M 上的声子频率，如图和附录1所示。
 % 在拉曼散射中，起作用的模式都是那些非常接近于 Gamma 的模式
 %   （如图中的点所示，分为位于 1/50 和 1/100 处，这两条线分别对应于拉曼散射在 z 方向入射/散射和 y 方向入射/散射）。