Open AccessElectric Field–Controlled Multistep Proton Evolution in H x SrCoO 2.5 with Formation of H–H Dimer
Author(s) -
Li HaoBo,
Lou Feng,
Wang Yujia,
Zhang Yang,
Zhang Qinghua,
Wu Dong,
Li Zhuolu,
Wang Meng,
Huang Tongtong,
Lyu Yingjie,
Guo Jingwen,
Chen Tianzhe,
Wu Yang,
Arenholz Elke,
Lu Nianpeng,
Wang Nanlin,
He Qing,
Gu Lin,
Zhu Jing,
Nan CeWen,
Zhong Xiaoyan,
Xiang Hongjun,
Yu Pu
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201901432
Subject(s) - ionic bonding , ion , chemical physics , materials science , proton , crystallography , valency , dimer , chemistry , physics , organic chemistry , quantum mechanics , linguistics , philosophy
Ionic evolution–induced phase transformation can lead to wide ranges of novel material functionalities with promising applications. Here, using the gating voltage during ionic liquid gating as a tuning knob, the brownmillerite SrCoO 2.5 is transformed into a series of protonated H x SrCoO 2.5 phases with distinct hydrogen contents. The unexpected electron to charge‐neutral doping crossover along with the increase of proton concentration from x = 1 to 2 suggests the formation of exotic charge neutral H–H dimers for higher proton concentration, which is directly visualized at the vacant tetrahedron by scanning transmission electron microscopy and then further supported by first principles calculations. Although the H–H dimers cause no change of the valency of Co 2+ ions, they result in clear enhancement of electronic bandgap and suppression of magnetization through lattice expansion. These results not only reveal a hydrogen chemical state beyond anion and cation within the complex oxides, but also suggest an effective pathway to design functional materials through tunable ionic evolution.