可视化研究胶体体系中超稳定非晶结构态振动模

Glassy materials are none crystalline solids. Although structures of glass are amorphous, their microscopic structure components, together with the formation kinetics remind a big mystery. Compared with their crystalline counterparts, glassy materials are metastable. However, recent studies revealed glassy materials much more stable than conventional ones, namely the ultra-stable glass, which supprisingly has potential energy very close to crystal. A unique feature in the vibrational density of states of ultra-stable glass is the much higher Boson peak frequency than conventional glass. Up to now, what is the microscopic structure profile of unltra-stable glass and how does it cause the uniqe Boson peak are completely unknown, which can be best clarified by single particle level experiments. In a recent publication (Review Letters 108, 095501（2012)), the applicant experimental studied the low frequency quasilocalized modes in glass, which suggests a strong research background on such a project. In colloidal glass sysmtems, by using three-D imaging, optically tweeing particles and covariance matrix methods, the applicant plans to visualize the detailed structure components and vibrational modes of ultra-stable glass at single particle level, and clarify a microscopic origion of the unique Boson peak.

非晶态材料也叫无定型或玻璃态材料，然而，非晶固体的结构种类及其成因（玻璃化转变）是目前科学界尚未解决的难题之一。与对应的晶体态相比，传统的理论认为非晶态固体都是亚稳态。然而，近年来研究者发现超稳定玻璃态结构的能量大大低于普通玻璃态，非常逼近对应晶体结构的能量。超稳定玻璃态的一个重要物理特征是其振动模式态密度的玻色峰与普通玻璃态相比处于较高的频率。然而，到目前为止，超稳定玻璃态的精细微观结构以及这些微观结构怎样改变超稳定玻璃态物理特性并不为人所知。申请人在对二维胶体玻璃态的振动模式态密度研究中(Physical Review Letters 108, 095501（2012）)发现不同种类的非晶微观结构对振动模式的玻色峰贡献并不相同。申请人计划在胶体系统中用多光镊技术对玻璃态结构进行精确操控，并利用协方差矩阵方法，单颗粒尺度可视化研究体系本征振动模式，探索各种微观结构如何影响波色峰的特性。

非晶态材料也叫无定型或玻璃态材料，然而，非晶固体的结构种类及其成因（玻璃化转变）是目前科学界尚未解决的难题之一。近年来研究者发现超稳定玻璃态结构的能量大大低于普通玻璃态，非常逼近对应晶体结构的能量。超稳定玻璃态的一个重要物理特征是其振动模式态密度的玻色峰与普通玻璃态相比处于较高的频率。然而，到目前为止，超稳定玻璃态的精细微观结构以及这些微观结构怎样改变超稳定玻璃态物理特性并不为人所知。本项目利用协方差矩阵方法，单颗粒尺度可视化研究体系本征振动模式，探索各种微观结构如何影响波色峰的特性，研究发现不同种类的非晶微观结构对振动模式的玻色峰贡献并诱发玻色峰的机制。研究成果发表于H.C.Shen, P. Tan* and L. Xu*, “Probing the role of mobility in the collective motion of nonequilibrium systems.” Phys. Rev. Lett. 116 048302 (2016).（编辑推荐）