论文标题
2H-NBSE $ _2 $探索的照片兴趣频率工程由时间和角度分辨光学光谱探测
Photo-excitation band-structure engineering of 2H-NbSe$_2$ probed by time- and angle-resolved photoemission spectroscopy
论文作者
论文摘要
我们研究了按时间和角度分辨光发射光谱法研究了2H-NBSE $ _2 $的非平衡电子结构。我们发现，频带结构是由强烈的照相兴奋而独特地调节的，这表明了e $ _f $的光电强度的异常增加。为了深入了解观察到的光诱导的电子状态，我们使用了调制的晶格结构进行了DFT计算，并发现NB层SE高度的变化导致有效质量和带隙能的显着变化。我们进一步研究动量依赖性载体动力学。结果表明，在以K为中心的费米表面上的弛豫比以$γ$以$γ$为中心的费米表面更快，这可以归因于在以k为中心的费米表面上更强的电子晶体耦合。我们对带结构工程的演示表明，光作为控制固态材料功能的工具的新作用。
We investigated the nonequilibrium electronic structure of 2H-NbSe$_2$ by time- and angle-resolved photoemission spectroscopy. We find that the band structure is distinctively modulated by strong photo-excitation, as indicated by the unusual increase in the photoelectron intensities around E$_F$. In order to gain insight into the observed photo-induced electronic state, we performed DFT calculations with modulated lattice structures, and found that the variation of the Se height from the Nb layer results in a significant change in the effective mass and band gap energy. We further study the momentum-dependent carrier dynamics. The results suggest that the relaxation is faster at the K-centered Fermi surface than at the $Γ$-centered Fermi surface, which can be attributed to the stronger electron-lattice coupling at the K-centered Fermi surface. Our demonstration of band structure engineering suggests a new role for light as a tool for controlling the functionalities of solid-state materials.
