Pressure along with temperature and chemical composition defines the state of matter. High pressure could decrease the distance among atoms, shorten the chemical bonds, and distort the electron orbitals. Beyond a certain pressure point, materials may reach a new state of equilibrium and transit into a phase with distinctive atomic arrangement and crystal structure exhibiting properties quite different from that stable phase at ambient conditions. For example, under high pressure soft and black graphite transforms into a superhard and light-transparent diamond. With the rapid development of technology (high pressure generation apparatus, synchrotron X-ray, Raman), high-pressure technique has become a prevalent and important tool for exploring the unique nature of matter in solid, liquid, or gaseous state under extreme conditions. The most popular apparatus for the generation of high pressure is a small vise-like device called diamond anvil cell, consisting of two opposite diamonds with tiny tips. Pressing two anvils, between which the sample is located, can create pressure as high as that in the earth’s core (~360 GPa). Because of diamond’s transparency over a broad frequency of electromagnetic radiations (X-ray, Raman, visible light, etc.), we can do the in-situ measurements by integrating diamond anvil cell with characterization facilities (Synchrotron X-ray, Raman spectroscope, and so on) By taking advantage of high-pressure technique, Dr. Wang’s research focuses on the study of material’s optical property, elasticity, plasticity, phase stability, chemical reactivity, and microstructure evolution (defects, grain size, and grain boundaries), as well as the synthesis of new materials under pressure conditions.
Biography Updated on 2 April 2012