Speaker

Tiange Bi

Earth and Planets Laboratory of the Carnegie Institution for Science

Date＆Time

2022.06.02（Thur）AM 10:00

Location

Zoom Meeting ID：950 680 6742 Password：2022

Reporter

Tiange Bi is a Postdoctoral Fellow working with Timothy Strobel, Ronal Cohen, and Peter Driscoll. She received her Ph.D. under supervision of Prof. Eva Zurek in chemistry from the University of New York at Buffalo in 2020. Her research is concerned with crystal structure prediction of new clathrate structures, and theoretical studies of the transport properties of iron alloys in the Earth and planetary cores. She published 19 papers including J. Am. Chem. Soc., Angew. Chem. Int. Ed. et al. She is Condensed Matter: Editorial Board Member. She is also a receipt of APC DCOMP student travel award and 2020 best PhD dissertation award.

Abstract

It has been proposed that hydrogen will become an alkali metal-like mono atomic solid under pressure, with a high superconducting critical transition temperature, Tc, because it is the lightest element (has large phonon frequencies), does not have any core electrons, forms strong covalent bonds (resulting in a large electron-phonon coupling), and has wide bands with substantial density of states at the Fermi Level.  All these qualities would make it a good conventional superconductor. However, up to the center of the Earth pressures as achieved in diamond anvil cell (DAC) experiments, researchers haven’t created this form of hydrogen. Our research mainly focuses on hydrogen-rich materials because it has been proposed that the metallization pressure of hydrogen could be decreased via “chemical precompresion”. We have carried out EA searches to explore the phase diagram of compressed hydrides, and to identify the stable or metastable structures. Next, we have calculated the electron-phonon coupling (EPC) parameters. Then, we estimated Tc values using the Allen-Dynes modified McMillan Equation and/or by numerically solving the Eliashberg equations. Using this method, we have successfully investigated phosphorus hydrides, iron hydrides, C-S-H, and Li-F-H systems.