Spectral Persistence and the Anharmonic Dynamics of Solids

摘要本实验研究的重点是确定晶体和玻璃中多种弹性构型的静态和动态特性。该方法是利用各种线性和非线性光谱工具，包括持续红外光谱孔燃烧、红外泵浦探针瞬态孔燃烧、拉曼散射和傅里叶变换红外光谱，研究固体低洼平衡态和非平衡态和构型之间的能量传输。由于晶格的非调和性，本征定域模式可能存在于大块晶体的表面或边缘，这一可能性引起了人们的兴趣。局域振动模态研究的进展，带动了对其他非线性动力系统的本征局域激励的探索。反铁磁晶体为寻找本征局域激发提供了新的实验机会。摘要在凝聚态物理学中，一个突出的问题是确定晶体和玻璃中近平衡振动状态的静态和动态行为的来源。本文提出的方法是用各种光谱工具来研究低洼平衡态和非平衡态固体之间的能量传递。最近，人们对一种新型局域振动激发的可能性越来越感兴趣，这种局域振动激发可能是由块状晶体中存在的晶格非线性引起的，这种非线性可能存在于它们的表面或边缘。这方面的进展导致了对非线性磁系统的本征局域激励的探索。提议的测量应该影响到各种各样的主题，如用于信息存储、放大和光传输的光学材料中的结构缺陷的作用，以及快离子导体和磁性结构的科学和技术。＊＊＊

9631298 Sievers Technical Abstract The proposal experimental study focuses on identifying the static and dynamic properties of multiple elastic configurations in crystals and glasses. The method is to examine the energy transport between the low lying equilibrium and non-equilibrium states and configurations of solids with a variety of linear and nonlinear spectroscopic tools, including persistent IR spectral hole burning, IR pump-probe transient hole burning, Raman scattering and fourier transform IR spectroscopy. Interest has grown in the possibility that intrinsic localized modes, made possible by the lattice anharmonicity, may exist in bulk crystals, at their surfaces or at their edges. The progress in localized vibrational mode studies is leading to the exploration of intrinsic localized excitations in other nonlinear dynamical systems. Antiferromagnetic crystals provide new experimental opportunities to search for intrinsic localized excitations. %%% Non-Technical Abstract An outstanding problem in condensed matter physics is identifying the source of the static and dynamic behavior of near-equilibrium vibrational states in crystals and glasses. The proposed method is to examine the energy transport between the low lying equilibrium and non- equilibrium configurations of solids with a variety of spectroscopic tools. Recently, interest has grown in the likelihood of a new type of localized vibrational excitation made possible by the lattice nonlinearity that may exist in bulk crystals, at their surfaces or at their edges. Progress here is leading to the exploration of intrinsic localized excitations in nonlinear magnetic systems. The proposed measurements should impact on topics as diverse as the role of structural defects in optical materials used for information storage, amplification and optical transmission, and on the science and technology of fast-ion conductors and that of magnetic structures. ***