Time：14:00-15:30, Tuesday, Jan. 19^th, 2021

Host: Dr. Jie Wu, PI of School of Science, Westlake University

Venue: Room 211, Building 4, Yunqi Campus, Tencent Video Conferencing

Online: Tencent Video Conferencing ( Meeting ID: 776 504 168)

Speaker：

Prof. Pu Yu

Department of Physics, Tsinghua University

Biography:

Prof. Pu Yu received his Ph. D. in Physics from UC Berkeley in 2011. After postdoc stay at Berkeley and RIKEN, he joined the faculty of Tsinghua University as an Assistant professor in 2012, and was promoted to Associate Professor in 2017 and then Professor in 2018. He also held a joint Unit-Leader position in RIKEN Center for Emergent Matter Science from 2014. His current research interests lie in the understanding and designing novel electronic states within complex oxide heterostructures. 

Abstract:

Due to the strong electron-ion interaction, ionic evolutions within complex oxides forms a productive avenue for designing novel material functionalities with extensive applications. In this talk, I will first introduce a simple approach to achieve reversible and nonvolatile electric-field control of oxygen and hydrogen ionic evolutions within the model system of brownmillerite SrCoO_2.5 through ionic liquid gating. Due to the selectively controllable ionic evolutions, we achieved a tri-state phase transformation among SrCoO_2.5, its counterpart of perovskite SrCoO_3-δ and a hitherto-unexplored HSrCoO_2.5 phase with distinct magnetic, electrical and optical properties, which suggest interesting tri-state magnetoelectric and electrochromic effects. Furthermore, the newly discovered HSrCoO_2.5 phase forms a conceptually new solid oxide electrolyte at low temperature region owing to its extremely-high proton concentration and well-ordered vacancy channels. We envision and further demonstrate that the electric-field controlled ionic evolution brings in a new tuning knob to manipulate the coupling and correlation between charge, spin, orbital and lattice degrees of freedom and paves a new playground for the discovery of novel materials with rich functionalities.

Contact:

School of Science, Ms. Zhong, zhongmengzhen@westlake.edu.cn