Dark excitons: Energetics, dynamics, transport and correlated phases

暗激子：能量学、动力学、输运和相关相

• 批准号: 535247173
• 负责人: Professor Dr. Stefan Mathias
• 金额: --
• 依托单位: I. Physikalisches Institut - Festkörper- und Tieftemperaturphysik -
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/535247173?language=en
• 关键词: Dark; excitons; Energetics; dynamics; transport

We aim to explore the energetics, dynamics, transport properties and correlated interactions of intralayer, hybrid and interlayer excitons in two-dimensional semiconductors. While experimental research in this direction is well established, our project provides a complementary and powerful approach to open research questions: In our preliminary work, we have developed a new generation time- and angle-resolved photoemission spectroscopy (trARPES) experiment that can be applied to exfoliated and artificially stacked van-der-Waals heterostructures; the formation and thermalization dynamics of bright and dark excitons can be accessed on ultrashort time- and length-scales (55 fs time-, 150 meV energy-, 0.04 1/A momentum- and 500 nm spatial-resolution). In the SPP, we will make use of the full capabilities of trARPES to study the spatio-temporal dynamics of bright and dark excitons in exfoliated heterostructures of transition metal dichalcogenides (TMDs). Specifically, by tuning the moiré wavelength (i.e., the twist-angle), by suppressing interlayer hybridization by hexagonal boron nitride (hBN) decoupling layers and by creating local strain gradients, we aim to control the dynamics and correlated interactions of excitons in space and time. We will focus on three objectives: First (i), we will study the impact of exciton confinement and flat band physics onto the formation and thermalization dynamics of bright and dark excitons in TMD/TMD and TMD/hBN/TMD heterostructures. Second (ii), in order to experimentally characterize diffusion processes of bright and dark excitons, we will monitor the spatio-temporal exciton dynamics in the presence of the moiré potential, hBN decoupling layers and local strain gradients. And third (iii), we will investigate the creation and stabilization of dark exciton condensates in TMD/hBN/TMD heterostructures. Beyond the established experimental approaches, we will make use of momentum-resolved photoemission technique and orbital tomography in order to study exciton condensates from the perspective of the exciton’s real-space wavefunction.

我们旨在探索二维半导体中内层，混合和层间激子的能量，动力学，传输特性以及相关的相互作用。虽然朝这个方向良好的实验研究确定，但我们的项目提供了一种完整而有力的方法来开放研究问题：在我们的初步工作中，我们开发了新一代的时间和角度分辨的光发射光谱（Trarpes）实验，可以应用于剥落和人工堆叠的Van-der-der-der-der-der-der-der-der-Waals杂物；可以在超短时间和长度尺度上访问明亮和深色激子的形成和热动力学（55 FS Time-，150 MeV Energy-，0.04 1/A动量 - 和500 nm的空间分辨率）。在SPP中，我们将利用Trarpes的全部能力研究过渡金属二甲植物（TMDS）的去角质异质结构中明亮和深色激子的时空动力学。具体而言，通过调整Moiré波长（即扭曲角），通过抑制六角形硝酸硼（HBN）去耦合层并通过创建局部应变梯度来抑制层间杂交，我们旨在控制空间和时间激素的动力学和相关性相互作用。我们将重点关注三个目标：首先，我们将研究激子限制和扁平频带物理学对TMD/TMD和TMD/TMD/HBN/TMD异质结构中明亮和深色激子的形成和热动力学的影响。第二（iii），为了实验表征明亮和深色激子的差异过程，我们将在存在Moiré电位，HBN解耦层和局部应变梯度的情况下监视时空的刺激动力学。和第三（iii），我们将研究TMD/HBN/TMD异质结构中深色激子冷凝物的创造和稳定。除了既定的实验方法之外，我们还将利用动量分辨的光发射技术和轨道断层扫描，以便从令人兴奋的真实空间波函数的角度研究令人兴奋的冷凝水。