Pump-probe ARPES for Studies of Electron and Phonon Dynamics in Novel Materials

非技术摘要利用一种新开发的时间分辨角度分辨光电子能谱系统，将确定各种重要材料中电子相互作用的动力学。重点将放在“关联电子”系统上，包括高温超导体和电荷密度波系统，其中电子相互作用或关联尤为重要。该项目的总体目标和智力优势的基础将是确定固体各种激发态的动力学，并最终通过适当定制的超快光抽运脉冲来控制这些过程。这些目标直接涉及两个重大挑战：“物质的显著性质如何从原子或电子成分的复杂相互关系中显现出来，以及我们如何控制这些性质？”以及“如何描述和控制物质远离--特别是远离--平衡？”除了上面讨论的科学影响外，本研究项目还强调了学生的亲密参与，因为这是吸引有才华的本科生并将他们留在科学和工程职业生涯的最有效方式之一。四名本科生目前正在从事与该项目相关的项目。PI还将扩展一系列积极的外展项目，其中将包括从中学生到高级研究人员和专业人员的全方位教育和外展。技术摘要利用新开发的时间分辨角度分辨光电子能谱(TrARPES)系统，将确定各种重要材料类中电子相互作用的动力学。重点将放在“相关电子”系统上，包括高温超导体、电荷密度波系统和Mott绝缘体。TrARPES仍然处于初级阶段，尽管这项新技术的力量是显而易见的，因为它将ARPES的力量与超快光谱和相干控制领域结合在一起。与以前的trARPES系统相比，新系统具有许多优势，包括a)在保持时间带宽限制或接近时间带宽限制的同时提高了能量分辨率。B)改进了系统泵浦方式的选择性和可控性，包括光子能量的宽可调谐以及高泵浦功率，从而使电荷和声子的定制共振泵浦成为可能。TRARPES实验将与在同一组中对相似或相同材料进行的静态(单光子)激光和同步辐射-ARPES实验紧密结合。除了上面讨论的科学影响外，本研究项目还强调了学生的亲密参与，因为这是吸引有才华的本科生并将他们留在科学和工程职业生涯的最有效方式之一。四名本科生目前正在从事与该项目相关的项目。PI还将扩大一系列积极的外联项目，其中将包括从中学生到高级研究人员和专业人员的全方位教育和外联。

Nontechnical abstract Utilizing a newly developed time-resolved angle-resolved photoemission ARPES system, the dynamics of electron interactions in a variety of important classes of materials will be determined. The focus will be on "correlated electron" systems including high transition temperature superconductors and charge density wave systems, in which the electronic interactions or correlations are especially important. The general goal and the basis of the intellectual merit of the project will be to determine the dynamics of various excited states of a solid and ultimately to control these processes through suitably tailored ultrafast optical pump pulses. These goals directly relate to two grand challenges: "How do remarkable properties of matter emerge from complex correlations of the atomic or electronic constituents and how can we control these properties?" and "How can matter be characterized and controlled away from - especially very far away - from equilibrium?". In addition to the scientific impacts discussed above, the intimate inclusion of students in this research program is emphasized as it is one of the most effective ways to attract talented undergraduates and retain them in careers in science and engineering. Four undergraduate research students are currently working on projects related to this program. The PI will also expand upon a set of active outreach projects, which will include education and outreach over the full range from middle-school students to advanced researchers and professionals.Technical abstract Utilizing a newly developed time-resolved angle-resolved photoemission ARPES (trARPES) system, the dynamics of electron interactions in a variety of important classes of materials will be determined. The focus will be on "correlated electron" systems including high transition temperature superconductors, charge density wave systems, and Mott insulators. trARPES is still in its infancy, though the power of this new technique is clear because it brings the powers of ARPES together with the field of ultrafast spectroscopy and coherent control. The new system includes a number of advantages compared to previous trARPES systems, including a) improved energy resolution while staying at or near the time-bandwidth limit. b) Improved selectivity and control in how the system is pumped, including wide tunability of photon energies as well as high pump power, giving the possibility for tailored resonant pumping of charges and phonons. The trARPES experiments will be closely coupled with static (single photon) laser and synchrotron-ARPES experiments performed in the same group on similar or identical materials. In addition to the scientific impacts discussed above, the intimate inclusion of students in this research program is emphasized as it is one of the most effective ways to attract talented undergraduates and retain them in careers in science and engineering. Four undergraduate research students are currently working on projects related to this program. The PI will also expand upon a set of active outreach projects, which will include education and outreach over the full range from middle-school students to advanced researchers and professionals.