软物质非晶固体本征振动模的理解、应用及调控

Normal modes of vibration are fundamental in the determination of properties of solids. Due to the lack of long range order, noncrystalline solids show distinct vibrational features from crystals, e.g. low-frequency quasilocalization of normal modes of vibration and boson peak. The mechanisms of the special vibrational features and their links to the dynamics of disordered systems and noncrystalline liquid-solid transition are cutting-edge research topics in today's soft condensed matter physics. In this project, we plan to study the effects of various factors.inducing disorder such as the distribution of interaction, distribution of mass, and temperature on the vibrational properties of noncrystalline solids, and investigate systematically the underlying mechanisms of the low-frequency quasilocalization and boson peak in noncrystalline solids, using soft colloids as the object of study. We also plan to apply our knowledge of normal modes of vibration to understand some interesting and novel phenomena in physical processes such as the noncrystalline liquid-solid transition and energy transport. Furthermore, we will attempt to modulate the vibrational properties of normal modes of vibration of noncrystalline solids by manipulating the particle constraints, and consequently modulate the material, dynamic, and phase transition properties of disordered systems. Through the theoretical study, application, and modulation of normal modes of vibration, we wish to obtain more thorough and deeper understanding of the vibrational properties of non-crystalline solids.

固体的本征振动模是决定固体性质的基础。非晶固体由于长程有序性的缺失形成有别于晶体的特有振动特性，如低频本征振动模的准局域化和低频振动模聚集而成的玻色峰。这些振动特性的形成机制及其与非晶体系的动力学、非晶液-固转变等的关联是目前软凝聚态物理的前沿课题。本项目计划以软物质胶体系统为研究对象，通过研究各种造成体系无序的因素，如作用势分布、质量分布、温度等对非晶固体振动特性的影响，系统探讨非晶固体本征振动模准局域化和玻色峰的形成机制。在深入了解非晶固体振动特性的基础上，我们将运用本征振动模的性质来理解非晶液-固转变、能量输运等实际物理过程中出现的一些新奇有趣的现象。此外，我们还将尝试通过人为控制粒子的运动来实现对非晶固体本征振动模特性的调控，并进而调控非晶体系的材料、动力学和相变性质。我们希望可以通过本项目的开展，从理论、应用和调控等多角度对非晶固体的振动特性有更全面和深入的认识。

在本项目的支持下，我们开展了非晶固体本征振动模的相关研究，进一步深入探讨了非晶固体本征振动模特性的形成机理、深化了对非晶固体本质的认识，并且在研究过程中发现了一些新的现象、拓展了研究内容，包括超材料、二维熔化机理等。项目基本达成了预定研究目标，取得了一系列重要进展，共发表了12篇SCI论文，其中包括4篇Phys. Rev. Lett.。代表性的成果包括：探讨了各类结构无序在非晶固体本征振动特性形成中扮演的角色，并意外发现了通过引入关联无序形成负泊松比超材料的新途径；表征了本征振动模在非晶固体负载失稳过程中的重要作用及非晶固体的非简谐性；发现了由本征振动模定义的结构参量与Jammed固体的临界稳定性之间的关联；发现了高密度软芯粒子体系的二维熔化存在由非连续到连续相变的转变；揭示了玻璃形成体系的结构弛豫与动力学异质性的内在关联，等等。