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2025-07-05 19:26:34 +08:00
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@@ -45,21 +45,35 @@ It should be noted, however, that the observability in Raman experiment depends
因此,拉曼张量的大小可以在进一步的第一性原理计算之前给出,结果总结在表中。
我们的结果表明756 附近的峰应该比其它峰具有更强的拉曼强度。
A method to estimate the magnitudes of the Raman tensors based on symmetry analysis was proposed.
A method to rapidly estimate the magnitudes of the Raman tensors was proposed (see appendix for details).
This approach is founded on the symmetry analysis and incorporates the assumption
that the majority contribution of each atom to the Raman tensor is determined by its nearest neighbors
(denoted as $a_i$),
while contributions from more distant atoms are considered small (denoted as $epsilon_i$, $eta_i$, and $zeta_i$).
Additionally, we neglect the absolute differences in amplitudes of the same type of atoms in a phonon mode,
focusing only on their vibrational directions.
Consequently, the Raman tensors of the calculated phonon modes can be estimated
before additional first-principles computations (see appendix for details),
and the results are summarized in @table-nopol.
The parameters $a_i$ exhibit significantly larger absolute values compared to $epsilon_i$, $eta_i$, and $zeta_i$,
indicating the E#sub[2] mode at 756.25 cm#super[-1] in simulation (mode 8)
possess a much higher Raman intensity than the others.
that the primary contribution from each atom to the Raman tensor arises from its nearest neighbors (denoted as $a_i$),
while contributions from more distant atoms are much smaller (denoted as $epsilon_i$, $eta_i$, and $zeta_i$).
Furthermore, we neglect the absolute amplitude differences among atoms of the same type within a phonon mode,
considering only their vibrational directions.
This enables a preliminary estimation of the Raman tensor magnitudes prior to detailed first-principles calculations,
with the results summarized in @table-nopol.
Our analysis indicates that the E#sub[2] mode at 756.25 cm#super[-1] in simulation (mode 8)
should possess a much higher Raman intensity than the others.
我们使用第一性原理计算得到了拉曼张量的大小,并与我们的结果进行了比较。
#include "table-nopol.typ"
我们使用第一性原理计算得到了频率和拉曼张量的大小,并与我们的结果进行了比较。
声子频率和拉曼张量的大小被使用第一性原理计算,并与实验结果和理论预测进行了比较(@table-nopol)。
计算的声子频率与实验数据有很好的吻合,误差在 2-5% 之间,这个误差可能是由于 PBE 泛函对原子间力的低估cite
计算的拉曼张量也与实验和理论结果基本一致,这包括
强度最高的模式 E#sub[2] 776 cm#super[-1] 的实验(模式 8
其次是四个强度较低但在实验中清晰可见的模式,
包括 E#sub[2] 模式在 195.5 cm#super[-1](模式 1 203.3 cm#super[-1](模式 2
E#sub[1] 模式在 269.7 cm#super[-1](模式 3
A#sub[1] 模式在 609.5 cm#super[-1](模式 6
746 cm#super[-1](模式 7计算的 E#sub[1] 模式
756.25 cm#super[-1](模式 9计算的 E#sub[2] 模式
被预测具有更弱的拉曼强度,并且位于最强模式(模式 8附近使得它们在实验光谱中难以区分。
此外,在 812.87 cm#super[-1](模式 10计算的 A#sub[1] 模式
在基面极化配置xx yy仅为 0.01)中具有非常弱的拉曼强度,
但当偏振沿 z 轴时1.78)则显示出可观的强度。
The Raman tensors and frequencies of the negligible-polar phonons were calculated using first-principles methods,
and the results are compared with both experimental data and theoretical predictions (@table-nopol).
@@ -97,8 +111,6 @@ Besides, there are small peeks at xxx,
// 在论文中我们这样来称呼phonon 对应某一个特征向量,而 modes 对应于一个子空间。
// 也就是说,简并的里面有两个或者无数个 phonon但只有一个 mode
#include "table-nopol.typ"
#include "figure-raman.typ"
// TODO: 解释为什么 E1 可以看到

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@@ -17,20 +17,22 @@
- [x] 调整语言
- [ ] 坐标轴定义
- [ ] 偏振
- [x] 型总述
- [x] 无缺陷和点缺陷的模型大小、结构
- [x] 中文
- [x]
- [x] 填充数据和引用
- [ ] 点缺陷画图h k
- [x] 使用 inkscape 实现渐变
- [ ] 确定要展示哪些结构
- [ ] 点缺陷画图(复杂缺陷)
- [ ] 缺陷的模型大小、结构
- [/]
- [x] 模型总述
- [x] 无缺陷和点缺陷的模型大小、结构
- [x]
- [x] 英文
- [x] 填充数据和引用
- [ ] 点缺陷画图h k
- [x] 使用 inkscape 实现渐变
- [ ] 确定要展示哪些结构
- [ ] 缺陷画图(复杂缺陷)
- [ ] 面缺陷的模型大小、结构
- [/] 第一性原理计算和声子计算的工具
- [x] 中文
- [ ] 英文
- [ ] 填充数据和引用
- [ ] 拉曼强度的计算
- [/] results
- [x] 总述
- [/] 无缺陷
@@ -53,16 +55,19 @@
- [x] 中文
- [x] 英文
- [x] 调整语言
- [/] 表格
- [/] 示的表
- [x] 大致内容
- [ ] 可见性
- [/] 估算拉曼张量
- [x] 中文
- [x] 英文
- [ ] 调整语言
- [x] 调整语言
- [ ] 填充分离 Si C 结果的数据,对称分布小量
- [ ] 第一性原理计算
- [ ] 中文
- [ ] 模式的表格
- [x] 大致内容
- [ ] 调整、填充数据
- [/] 第一性原理计算
- [x] 中文
- [ ] 英文
- [ ] 调整语言
- [ ] 附录