CAREER: Pressure-Induced Amorphization and Materials Synthesis Under High Pressure Techniques

这是一个CAREER奖项目，涉及两个独立领域的高压技术研究。这项工作的一个目标是综合和研究新颖的和潜在技术相关的材料。本研究采用压力诱导非晶化，通过压力诱导破坏长程晶序来制备非晶材料。压力非晶化样品的x射线衍射研究将得到对相关函数G(r)。该函数的压力变化将与压力非晶化玻璃的结构与初始晶体以及与常规合成的熔融淬火玻璃的结构相关联。拉曼散射将用于研究这些玻璃的玻色子峰，这将导致对玻璃以及玻色子峰本身的更深层次的理解。许多理论研究预测了氮化碳各相的稳定性，一些理论研究表明某些相的体积模量应该与金刚石相相当。实现这种材料在理论上和实践上都引起了极大的兴趣。PI将对碳氮混合物施加高压和高温，以合成一些理论上预测的氮化碳的超硬相。研究材料的状态方程将有助于确定哪些相最有可能是超硬的，因此应该大量生产以进行更详细的研究。该项目的教育部分包括广泛的本科生研究活动、当地高中的讲座以及与美国物理学会当地学生分会相关的指导活动。这是一个CAREER奖项目，涉及高压（高达1亿大气压）技术，以合成和研究新颖和潜在的技术相关材料。最近观察到的一种技术是仅靠压缩就能把一个哭壶变成玻璃杯。这样就可以制作出各种各样的玻璃杯。x射线和光学散射技术将用于表征从晶体到玻璃态的结构转变。寻找新玻璃、初始晶体和传统模型玻璃之间的关系。第二个项目涉及使用高压来尝试合成新的超硬材料。与石墨转化为金刚石的过程类似，将对石墨-氮混合物施加高压和高温，试图合成一些理论上预测的氮化碳超硬相。该项目的教育部分包括广泛的本科生研究活动、当地高中的讲座以及与美国物理学会当地学生分会相关的指导活动。＊＊＊

9733956 Kruger This is a CAREER Award project involving high pressure techniques in two separate areas of research. An objective of the work is to synthesize and study, novel and potentially technologically relevant materials. The research employs pressure-induced amorphization, the pressure-induced destruction of long range crystalline order to produce an amorphous materials. X-ray diffraction study of pressure-amorphized samples will yield the pair correlation function, G(r). The pressure variation of this function will be correlate structures of the pressure-amorphized glasses with the starting crystals, as well as with conventionally synthesized, melt quenched glasses. Raman scattering will be used to study the boson peak of these glasses which will result in a deeper understanding of the glasses as well as the boson peak itself. Numerous theoretical studies have predicted the stability of various phases of carbon nitride, some theoretical studies indicating that certain phases should have bulk moduli rivaling that of diamond. There is significant interest, both theoretical, and practical, in realizing such materials. The PI will apply high pressures and high temperatures to carbon-nitrogen mixtures in order to synthesize some of the theoretically predicted superhard phases of carbon nitride. Study of the equation of state of the materials will help determine which phases are most likely to be superhard, and hence should be made in larger quantities for more detailed study. The education component of this project involves extensive undergraduate research activity, lectures at local high-schools, and mentoring activity associated with the local student Chapter of the American Physical Society. %%% This is a CAREER Award project involves high pressure (up to 100 million atmospheres) techniques to synthesize and study, novel and potentially technologically relevant materials. One relatively recently observed technique employs compression alone to turn a cry stal into a glass. In this way a variety of glasses will be prepared. X-ray and optical scattering techniques will be used to characterize the structural transition from the crystalline to the glassy state. Relationships are sought between the new glasses, the starting crystals, and traditional model glasses. A second project involves the use of high pressures to try to synthesis new, superhard materials. By analogy with the graphite to diamond conversion, high pressures and temperatures will be applied to graphite-nitrogen mixtures in an attempt to synthesize some of the theoretically predicted superhard phases of carbon nitride. The education component of this project involves extensive undergraduate research activity, lectures at local high-schools, and mentoring activity associated with the local student Chapter of the American Physical Society. ***