This commit is contained in:
2025-10-01 15:47:52 +08:00
parent b0dab166e9
commit a3d9b92558
9 changed files with 58 additions and 67 deletions

View File

@@ -75,8 +75,6 @@ E#sub[1]-2 和 E#sub[2]-4 模式位于最强模式 E#sub[2]-3 附近,且具有
使得它们在实验光谱中难以区分。
此外A#sub[1]-2 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,这导致它在正入射的拉曼实验中通常不可见;
但当偏振沿 z 轴时1.78)则显示出可观测的强度。
// E#sub[1]-1 模式在理论上无法在正入射中观察到,但在实验中仍然可以看到一个小峰。
// 这被认为是因为入射光并非完全沿z轴入射由于衬底斜切和共聚焦汇聚角。通过向不同方向倾斜衬底我们可以使这个峰变高或变低如附图所示这印证了我们的猜想。
The Raman tensors and frequencies of the negligible-polar phonons were calculated using first-principles methods,
and the results were compared with both experimental data and theoretical predictions (@table-nopol).
@@ -96,54 +94,29 @@ Additionally,
but showed an observable intensity when the polarization is along the z-axis (1.78).
Thus, it was not typically observed in normal incidence Raman experiments (cite),
but could be clearly detected in edge incidence configurations in our experiments.
// TODO: 这里缺两个引用
不同方向的入射配置会导致微小但可观测的峰位差异
理想情况下不允许存在的效应被观察到
这包括不同入射方向下,弱极性峰位的微小移动,以及 E#sub[1]-1 模式在正入射中的可见性。
在我们的计算中从正入射到肩入射E2-3的峰位几乎不变E2-1与A1-1会有可观测的蓝移同时E2-2会有可观测的红移。
实验结果与计算结果基本一致,如图如表所示。
E1模式在正入射中可以看到尽管理论上不应该。
这被认为是因为入射光并非完全沿z轴入射由于衬底斜切和共聚焦汇聚角。
不同方向偏振的结果印证了我们的猜想,如图所示。同时,略微倾斜衬底可以使这个峰变高或变低,如附图所示,这印证了我们的猜想。
微小但可观测的峰位移动应该存在于不同入射配置的峰位中,因为非零的波矢长度。
在我们的计算中相比于正入射肩入射的E2-1与E2-2的间距会减小0.49同时A1-1会红移0.19。
在实验中E2-1与E2-2的间距减少0.36A1-1红移了xxxx。
Minor but observable peak shifts of negligible-polar phonons were expected between different incidence configurations,
due to non-zero wavevector lengths.
Some effects absent in the ideal model were observed experimentally,
including minor but observable peak shifts of negligible-polar phonons between different incidence configurations,
and the observability of the E#sub[1]-1 mode in normal incidence Raman experiments.
The peak shifts were considered caused by the non-zero wavevector lengths of phonons.
In our calculations, compared to normal incidence,
the spacing between the E#sub[2]-1 mode and E#sub[2]-2 mode decreased by 0.49 cm#super[-1] under edge incidence,
while the A#sub[1]-1 mode redshifted by 0.19 cm#super[-1].
In our experiments, the spacing between the E#sub[2]-1 mode and E#sub[2]-2 mode decreased by 0.36 cm#super[-1],
while the A#sub[1]-1 mode redshifted by xxxx cm#super[-1].
the E#sub[2]-3 mode's frequency remained nearly unchanged,
while the E#sub[2]-1, E#sub[2]-2, A#sub[1]-1 modes exhibited minor but observable shifts.
The experimental results were in good agreement with our calculations, as shown in figure and table.
The visibility of the E#sub[1]-1 mode in normal incidence Raman experiments were attributed to the fact that
the incident light was not perfectly aligned along the z-axis,
due to the substrate's slight tilt and the converging angle of the confocal setup.
This was confirmed by the results under different polarization configurations and different tilt angles,
as shown in figure.
#include "figure-nopo-diff.typ"
E1为什么可以被看到。
E1在正入射中可以看到尽管理论上不应该。
这被认为是因为入射光并非完全沿z轴入射由于衬底斜切和共聚焦汇聚角。
通过向不同方向倾斜衬底,我们可以使这个峰变高或变低,如附图所示。
此外考虑到斜切方向x方向E1模式应该更容易在zxxz和zyxz中看到而在zyyz中更难看到这与实验一致。
The E#sub[1]-1 mode was observed in normal incidence Raman experiments, despite being theoretically forbidden.
This was attributed to the fact that the incident light was not perfectly aligned along the z-axis,
due to the substrate's slight tilt and the converging angle of the confocal setup.
This was confirmed by tilting the substrate in different directions,
which caused the peak to become more or less pronounced, as shown in the inset figure.
Furthermore, considering the tilt direction (x-direction),
the E#sub[1]-1 mode should be more easily observed in the zxxz and zyxz configurations,
while being more difficult to detect in the zyyz configuration,
which is consistent with our experimental observations.
#include "figure-e1.typ"
// 其它峰在其它章节中解释。
//
// Besides, there are other peeks in the experiment.
// The peek at 796 and 980 are caused by strong-polar phonons which will be discussed later.
// Besides, there are small peeks at xxx,
// which could not be explained in perfect 4H-SiC and will be discussed in the next section.
// TODO: 将一部分 phonons 改为 phonon modes
// 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 "figure-raman.typ"
// TODO: 解释为什么 E1 可以看到

View File

@@ -1,5 +1,5 @@
#figure(
image("/画图/弱极性不同方向偏移/main.svg"),
image("/画图/弱极性不同方向偏移/embed.svg"),
caption: [
(a) Phonon dispersion of 4H-SiC along the A#sym.GammaK high-symmetry path.
Gray lines represent negligible-polar phonon modes,

View File

@@ -5,6 +5,9 @@
let m(n, content) = table.cell(colspan: n, content);
let m2(content) = table.cell(colspan: 2, content);
let m3(content) = table.cell(colspan: 3, content);
let pm = sym.plus.minus;
let m21(content) = table.cell(rowspan: 2, colspan: 1, content);
let m22(content) = table.cell(rowspan: 2, colspan: 2, content);
table(columns: 12, align: center + horizon,
m2[*Notation of Mode*],
[E#sub[2]-1], [E#sub[2]-2], [E#sub[1]-1], m2[A#sub[1]-1],
@@ -19,22 +22,31 @@
// E2 E2 E1 A1 E1 E2 E2 A1
[Error (%)], [2.6], [2.7], [4.6], m2[2.9], [-], [2.5], [-], m2[3.1],
table.cell(rowspan: 4)[*Raman Tensor*],
[Non-zero components],
[Non-zero components],
// E2 E2 E1 A1
[xy, xx, -yy], [xy, xx, -yy], [xz, yz], [xx, yy], [zz],
// E1 E2 E2 A1
[xz, yz], [xy, xx, -yy], [xy, xx, -yy], [xx, yy], [zz],
[Analysis result (a.u.)],
// E2 E2 E1 A1
[$2epsilon_2-2zeta_2-4eta_2$], [$2epsilon_2-2zeta_2$], [$-2epsilon_1-2zeta_1$], [$-2epsilon_5$], [$-2epsilon_6$],
// E1 E2 E2 A1
[$-2epsilon_1+2zeta_1$], [$bold(8a_2)+2epsilon_2-2zeta_2-4eta_2$], [$-2epsilon_2+2zeta_2$], [$-2zeta_5$], [$-2zeta_6$],
[Calculation result (a.u.)],
// E2 E2 E1 A1 E1 E2 E2 A1
[0.17], [1.13], [2.43], [2.83], [1.79], [0.09], [88.54], [0.50], [0.01], [1.78],
[Experiment result #linebreak() (a.u.)],
// E2 E2 E1 A1 E1 E2 E2 A1
[0.15], [1.11], [], [1.64], [], [Invisible], [88.54], [Invisible], [Invisible], [],
[Analysis result (a.u.)],
// E2 E2 E1
[$2epsilon_2-2zeta_2-4eta_2$], [$2epsilon_2-2zeta_2$], [$-2epsilon_1-2zeta_1$],
// A1 E1 E2
[$-2epsilon_5$], [$-2epsilon_6$], [$-2epsilon_1+2zeta_1$], [$bold(8a_2)+2epsilon_2-2zeta_2-4eta_2$],
// E2 A1
[$-2epsilon_2+2zeta_2$], [$-2zeta_5$], [$-2zeta_6$],
[Calculation result (a.u.)],
// E2 E2 E1 A1 E1 E2 E2 A1
[0.17], [1.13], [2.43], [2.83], [1.79], [0.09], [88.54], [0.50], [0.01], [1.78],
[Experiment result #linebreak() (a.u.)],
// E2 E2 E1 A1 E1 E2 E2 A1
[0.15], [1.11], [], [1.64], [], [Invisible], [88.54], [Invisible], [Invisible], [],
table.cell(rowspan: 2)[*Raman Shift of Different Incidence Directions*],
[Calculation result (cm#super[-1])],
// E2 E2 E1 A1 E1 E2 E2 A1
[0.263], [-0.221], m21[-], m2[-0.188], m21[-], [0.004], m21[-], m22[-],
[Experiment result (cm#super[-1], average #pm standard deviation)],
// E2 E2 A1 E2
[0.158 #pm 0.060], [-0.245 #pm 0.026], m2[-0.279 #pm 0.016], [0 #linebreak() (used for calibration)],
)},
caption: [Negaligible-polarized Phonons at $Gamma$ Point.],
)<table-nopol>]

Binary file not shown.

Binary file not shown.

View File

@@ -1,2 +1,2 @@
1.954075029530483505e+02 1.953478857341484627e+02 1.953769267166200905e+02 1.954027970339571993e+02 1.953347589514454796e+02 1.953585750606797262e+02 1.953331279341388722e+02 1.954060267425776658e+02 1.952899705473047050e+02 1.953494452516382864e+02 1.953889540387470731e+02
1.955143254061939047e+02 1.955314568194222034e+02 1.955552683333574748e+02 1.955481750180620395e+02 1.955953344290883251e+02 1.955747288170350373e+02 1.955405035622480341e+02 1.954405635948803877e+02 1.953860875562799890e+02 1.955043177012716740e+02 1.955407037484820592e+02
1.955848052701602739e+02 1.955719549975438838e+02 1.955929051638321710e+02 1.956348447216788884e+02 1.954968231689395282e+02 1.955432332739998742e+02 1.955365842761710553e+02 1.956495763564502113e+02 1.955159160392721844e+02 1.956011491541673593e+02 1.956275997529293704e+02
1.958012278006910094e+02 1.958162272575077907e+02 1.957831178516572948e+02 1.958249159186141810e+02 1.958364298063405897e+02 1.957933101182395603e+02 1.958021374449715495e+02 1.958134637560016813e+02 1.957881271460675521e+02 1.958187264806561529e+02 1.957841759645648096e+02

View File

@@ -1,2 +1,2 @@
2.033596745420836385e+02 2.033350514440899133e+02 2.033520034103685248e+02 2.033359289059363277e+02 2.033325794937803437e+02 2.033390901492543037e+02 2.033161571980983240e+02 2.033605399415457100e+02 2.033257530283401309e+02 2.033291258845766265e+02 2.033518148664678051e+02
2.030969863890181841e+02 2.031161714659073425e+02 2.031116343498714230e+02 2.031200227998062076e+02 2.030973971095251045e+02 2.031188254080149420e+02 2.031087887206043661e+02 2.030768375231341452e+02 2.030640772958760749e+02 2.030605849463428854e+02 2.030720189180035788e+02
2.034024141958410041e+02 2.033769616315146891e+02 2.033951351274238277e+02 2.033767144659590258e+02 2.033742078065036765e+02 2.033807464342712876e+02 2.033596912050411163e+02 2.034018552200704733e+02 2.033676570593588053e+02 2.033706539863660225e+02 2.033939947741981484e+02
2.031269701456583903e+02 2.031410180043692435e+02 2.031354010942689854e+02 2.031408982509935299e+02 2.031211049500984416e+02 2.031478830793148802e+02 2.031381933050760722e+02 2.031074067250477526e+02 2.030943949028673501e+02 2.030889933216531062e+02 2.030979516775117872e+02