"Triple faced oxides” through electric-field controlled dual-ion switch with broad prospects in application
On June 1st 2017, a research group led by Associate Professor Pu Yu at department of physics in Tsinghua University published their seminal research work titled “Electric-field control of tri-state phase transformation with a selective dual-ion switch” in the prestigious journal Nature. This work reports for the first time the reversible and nonvolatile electric-field control phase transformations by dual-ion switches with the discovery of both the exotic tri-state electrochromic and magnetoelectric effects, which hold great potential in the optical, electrical and magnetic device applications.
Electric-field control of phase transformation with ion transfer is of great interest in materials and physics science with enormous and important practical applications, such as batteries, smart windows, fuel cells, etc. Increasing the number of transferrable ion species and of accessible crystalline phases could in principle greatly enrich material functionality. However, studies have so far focused mainly on the evolution and control of single ionic species (for example, oxygen, hydrogen or lithium ions), while electric-field control of phase transformation based on selective dual-ion has not yet been reported. Through the creative design, the research group realized the electric-field control of dual-ion (oxygen and hydrogen) tri-state phases transformation among the model system of brownmillerite SrCoO2.5 and its counterpart of perovskite SrCoO3-δ and a hitherto-unexplored HSrCoO2.5 phase by employing the ionic liquid gating. Because of the extremely distinct optical, electrical and magnetism properties among these three phases, this result can be readily applied to applications of electrochromic, resistive switch and magnetoelectric coupling devices, etc.
Furthermore, it is worth pointing out that, conventionally the strain (pressure) or chemical doping are widely employed to design/fabricate the materials with novel physical properties. While in this work, the electric-field control of dual-ion insertion and extraction and their corresponding tri-state phase transformation, offer a brand-new pathway to modulating the material functionalities, which can redesign the material functionalities even after the growth. More importantly, this method can be widely employed in a wide range of material systems to generalize exotic crystalline structures and novel physical properties.
This study was financially supported by the National？Basic Research Program of China, the National Natural Science Foundation of China, the Initiative Research Projects of Tsinghua University and the Beijing Advanced Innovation Center for Future Chip (ICFC).
Nianpeng Lu, Pengfei Zhang, Qinghua Zhang, Ruimin Qiao, Qing He, Haobo Li, Yujia Wang, Jingwen Guo, Ding Zhang, Zheng Duan, Zhuolu Li, Meng Wang, Shuzhen Yang, Mingzhe Yan, Elke Arenholz, Shuyun Zhou, Wanli Yang, Lin Gu, Ce-Wen Nan, Jian Wu, Yoshinori Tokura and Pu Yu, “Electric-field control of tri-state phase transformation with a selective dual-ion switch” Nature 546, 124 (2017).