Exploring electron-phonon interactions and coherent-phonon control of quantum materials using frequency-domain ARPES

使用频域 ARPES 探索量子材料的电子-声子相互作用和相干声子控制

• 批准号: 499426961
• 负责人: Professor Dr. Michael Bauer
• 金额: --
• 依托单位: Department of Mechanical Engineering and Materials Science and Engineering
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/499426961?language=en
• 关键词: Exploring; electron; phonon; interactions; coherent

Frequency-domain angle-resolved photoemission spectroscopy (FDARPES) – a technique based on the Fourier analysis of time-resolved ARPES (TRARPES) signals – is emerging as a promising experimental tool to investigate electron-phonon interactions in systems out of equilibrium. Beside revealing transient changes of the electronic structure due to the interaction with coherent phonons (in-phase vibrations of the crystalline lattice), it has been proposed as a new route to directly determine electron-phonon coupling matrix elements, and it can resolve transient changes in the spin-splitting of bands with unprecedented level of detail. Despite these unique characteristics, FDARPES has thus far seen application only in two experimental studies thus far. Goal of this project is to establish to which extent FDARPES may serve as a diagnostic tool to investigate light-driven phenomena in quantum matter. Specifically, in a combined experimental and theoretical effort, we aim at determining the capabilities of FDARPES in studying electron-phonon interactions, spin-orbit coupling, and coherent-phonon dephasing in condensed matter in a systematic and quantitative manner. We will conduct high-quality FDARPES experiments for the layered transition-metal dichalcogenides Td-MoTe2 and 1T’-MoTe2. These compounds exhibit a rich spectrum of coherent phonons, an important prerequisite for FDARPES measurements. Additionally, the two allotropes are connected by a phase transition which can be driven by light. We will explore the suitability of FDARPES to directly extract electron-phonon and phonon-phonon coupling matrix elements from the analysis of FDARPES intensities. We further aim to establish a rationale to control spin-splitting and the Rashba-Dresselhaus effect through the transient inversion-symmetry breaking induced by the excitation of coherent shear-phonon modes. Experimental investigations will be complemented by (i) state-of-the-art first-principles calculations of the electron-phonon interactions; (ii) the development of a new theoretical and computational framework to study the formation and dephasing of coherent phonons.

频域角分辨光谱学（FDARPES）是一种基于时间分辨光谱学（TRARPES）信号的傅里叶分析的技术，它正在成为一种有前途的实验工具，用于研究非平衡系统中的电子-声子相互作用。除了揭示与相干声子相互作用引起的电子结构的瞬态变化（晶格的同相振动）外，它还被提出作为直接确定电子-声子耦合矩阵元素的新途径，它可以以前所未有的详细程度解决能带自旋分裂的瞬态变化。尽管有这些独特的特性，FDARPES迄今为止只在两项实验研究中得到了应用。该项目的目标是确定FDARPES在多大程度上可以作为研究量子物质中光驱动现象的诊断工具。具体来说，通过实验和理论的结合，我们的目标是确定FDARPES系统和定量地研究凝聚态物质中电子-声子相互作用、自旋-轨道耦合和相干-声子脱相的能力。我们将对层状过渡金属二硫化物Td-MoTe2和1T ' -MoTe2进行高质量的FDARPES实验。这些化合物表现出丰富的相干声子光谱，这是FDARPES测量的重要先决条件。另外，这两个同素异形体通过一个可以由光驱动的相变连接起来。我们将从FDARPES强度分析中探讨FDARPES直接提取电子-声子和声子-声子耦合矩阵元素的适用性。我们进一步的目标是通过相干剪切声子模式激发引起的瞬态逆对称性破缺来建立控制自旋分裂和Rashba-Dresselhaus效应的理论基础。实验研究将由(i)电子-声子相互作用的最先进的第一性原理计算来补充；（ii）发展一个新的理论和计算框架来研究相干声子的形成和消相。