Equilibrium and non-equilibrium properties of the charge density wave condensate in quasi-one dimensional conductors

准一维导体中电荷密度波凝聚的平衡和非平衡性质

• 批准号: 5402294
• 负责人: Professorin Dr. Christine Kuntscher
• 金额: --
• 依托单位: Institut für Experimentalphysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2004-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5402294?language=en
• 关键词: Equilibrium; non; equilibrium; properties; charge

The proposed project aims at the understanding of the properties of the charge density wave (CDW) condensate in quasi-one dimensional conductors unter equilibrium and non-equilibrium conditions. The equilibrium properties will be studied by reflectivity measurements on single crystals from the microwave to the infrared/visible spectral range (2 cm -1-30000 cm-1), supplemented by dc-transport experiments. We are in particular interested in the low-frequency (i.e. microwave to far-infrared) range where the collective excitations of the CDW-condensate are observed. The influence of the sample quality and doping on the collective CDW-mode will be studied in a systematic way. We are furthermore interested in the effects of normal, i.e. uncondensed electrons on the collective CDW-mode, like screening and damping effects; these effects will be probed by measuring the reflectivity with a dc-electric field applied. The second main issue of the project is the study of the non-equlilibrium properties of the condensed CDW-state using time-resolved techniques: By optical pumping one can create a highly coherent condensed CDW-state. We plan to characterize this induced state by time-domain terahertz spectroscopy in the range 1 - 100 cm-1. We furthermor want to study the influence of single electrons on the amplitude mode of the CDW-using the pump-probe technique: By selective time-domain Raman-scattering one can coherently excite this mode and study its decay while a dc-electric field is applied.

该项目旨在了解平衡和非平衡条件下准一维导体中电荷密度波（CDW）凝聚体的特性。平衡特性将通过从微波到红外/可见光谱范围（2 cm -1-30000 cm-1）的单晶反射率测量来研究，并辅以直流传输实验。我们对低频（即微波到远红外）范围特别感兴趣，在该范围内观察到 CDW 凝聚体的集体激发。我们将系统地研究样品质量和掺杂对集体 CDW 模式的影响。此外，我们还对法向电子（即非凝聚电子）对集体 CDW 模式的影响感兴趣，例如屏蔽和阻尼效应；这些效应将通过测量施加直流电场的反射率来探测。该项目的第二个主要问题是使用时间分辨技术研究凝聚CDW态的非平衡特性：通过光泵浦可以创建高度相干的凝聚CDW态。我们计划通过 1 - 100 cm-1 范围内的时域太赫兹光谱来表征这种诱导态。我们还想使用泵浦探针技术研究单电子对 CDW 振幅模式的影响：通过选择性时域拉曼散射，可以相干地激发该模式并研究其衰减，同时直流电场是应用。