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)凝聚的性质。平衡性质将通过测量单晶从微波到红外/可见光(2 cm-1-30000 cm-1)的反射率，并辅之以直流输运实验来研究。我们特别感兴趣的是观察到CDW凝聚体集体激发的低频(即微波到远红外)范围。系统地研究了样品质量和掺杂对集体CDW模的影响。我们更感兴趣的是正常的，即未凝聚的电子对集体CDW模的影响，如屏蔽和衰减效应；这些影响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利用时间分辨技术研究凝聚态的非平衡性质：通过光抽运可以产生高度相干的凝聚态。我们计划在1-100厘米-1的范围内用时间域太赫兹光谱来表征这种感生状态。我们还想用抽运探测技术进一步研究单电子对CDW振幅模的影响：通过选择性的时间域拉曼散射，人们可以在外加直流电场的情况下相干地激发这个模，并研究它的衰变。