Bi $_2$ Te $_3$的扭曲狄拉克锥中反相相干声子的观测
Observation of antiphase coherent phonons in the warped Dirac cone of Bi$_2$Te$_3$
摘要：
在这个快速通信中，我们研究了激发电子和声子之间的耦合在高度各向异性的电子结构的拓扑绝缘体Bi $_2$ Te $_3$的原型。利用时间分辨和角度分辨光电子能谱，我们能够识别Bi $_2$ Te $_3$中的光学A $_{1g}$相干声子模的出现和超快时间演化。我们观察到的相干声子振荡的发病之间的$\overline{ΓK}$和$\overline{ΓM}$的高对称性方向，这是一致的翘曲的反相行为。我们的密度泛函理论计算和实验结果之间的定性协议揭示了狄拉克费米子和声子模式之间的各向异性耦合的拓扑绝缘体Bi $_2$ Te $_3$的关键作用。
英文摘要：
In this Rapid Communication we investigate the coupling between excited electrons and phonons in the highly anisotropic electronic structure of the prototypical topological insulator Bi$_2$Te$_3$. Using time- and angle-resolved photoemission spectroscopy we are able to identify the emergence and ultrafast temporal evolution of the longitudinal-optical A$_{1g}$ coherent-phonon mode in Bi$_2$Te$_3$. We observe an antiphase behavior in the onset of the coherent-phonon oscillations between the $\overline{ΓK}$ and the $\overline{ΓM}$ high-symmetry directions that is consistent with warping. The qualitative agreement between our density-functional theory calculations and the experimental results reveals the critical role of the anisotropic coupling between Dirac fermions and phonon modes in the topological insulator Bi$_2$Te$_3$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
