Dielectric Properties of Ice

讲座标题:Dielectric Properties of Ice

主讲人: 晏飞翔 博士 (中科院合肥物质科学研究院)

讲座时间:2015-10-23 13:00





  H2O is arguably one of the most studied substances; though yet, the more we study it the more complicated we find it to be. In this talk, I will first discuss the alternative preparation method and measuring technique we took in preparing 99.9% pure (undoped) crystalline samples of H2O ice with the use of double piston cell cylinders and diamond anvil cell assemblies. I will then discuss data taken from temperature sweeps of the complex dielectric constant at different hydrostatic pressures as well as isothermal and isobaric dispersion & absorption dielectric spectroscopy. From such experiments, we verified the presence of various phase boundary lines and triple points between the many phases of ice that were previously only conjectured to exist. In addition, a new phase boundary pertaining to the melting of cubic ice along with the existence of a second critical point in water is discovered. Lastly, distinct dielectric anomalies indicate that correlated proton tunneling indeed occurs at low temperatures exhibiting an apparent quantum isotope effect. By treating the protons as a Bose-Einstein condensate, it is shown that a new type of macroscopic quantum phenomena in the form of correlated proton tunneling exists in ice; that quantization also exists; and that an order parameter in the form of an internal ac electric field exists upon entering the ground state.


  Fei Yen was born in San Antonio, Texas in 1980. He obtained his BS (2002), MS (2003) and PhD (2007) degrees all in physics and all at the University of Houston. From 2009-2013, Dr. Yen was an associate professor at Southwest Jiaotong University. In 2013, he began his appointment as an associate researcher at the Institute of Solid State Physics, Chinese Academy of Sciences and holds a joint appointment as a faculty scientist at the High Magnetic Field Laboratory, Chinese Academy of Sciences. As a junior scientist, Dr. Yen has been part of over 50 publications, been cited over 700 times, and has an H-index of 13. His research interests are on phase transitions and critical phenomena of condensed matter under various types of extreme conditions.

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