arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1508.01769cond-mat.mtrl-sci
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六方氮化硼的激子能量-动量图

Exciton energy-momentum map of hexagonal boron nitride

Giorgia Fugallo, Matteo Aramini, Jaakko Koskelo, Kenji Watanabe, Takashi Taniguchi, Mikko Hakala, Simo Huotari, Matteo Gatti, Francesco Sottile

摘要:

理解和控制激子在固体中传播的方式是定制具有改进的光电性能的材料的关键。在这个方向上的一个基本步骤是激子能量动量色散的测定。在这里,由于无参数的Bethe-Salpeter方程(BSE)的解决方案,我们绘制和解释的前三个布里渊区的六方氮化硼(h-BN)的激子能量-动量图。我们发现,h-BN显示出强烈的激子效应,不仅在光学光谱中消失的动量$\mathbf{q}$,如前所述,但也在大$\mathbf{q}$。我们通过非弹性X射线散射(IXS)实验评估计算的激子图来验证我们的理论预测。此外,我们解决了以前的实验数据和计算之间的差异,然后证明BSE是高度准确的,通过整个动量范围。因此,这些结果提出了BSE和IXS的组合作为解决复杂材料中激子动力学的工具的选择。

英文摘要:

Understanding and controlling the way excitons propagate in solids is a key for tailoring materials with improved optoelectronic properties. A fundamental step in this direction is the determination of the exciton energy-momentum dispersion. Here, thanks to the solution of the parameter-free Bethe- Salpeter equation (BSE), we draw and explain the exciton energy-momentum map of hexagonal boron nitride (h-BN) in the first three Brillouin zones. We show that h-BN displays strong excitonic effects not only in the optical spectra at vanishing momentum $\mathbf{q}$, as previously reported, but also at large $\mathbf{q}$. We validate our theoretical predictions by assessing the calculated exciton map by means of an inelastic x-ray scattering (IXS) experiment. Moreover, we solve the discrepancies between previous experimental data and calculations, proving then that the BSE is highly accurate through the whole momentum range. Therefore, these results put forward the combination BSE and IXS as the tool of choice for addressing the exciton dynamics in complex materials.

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。

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