Chen Wei-Tin, Nishikubo Takumi, Sakai Yuki, Das Hena, Fukuda Masayuki, Pan Zhao, Ishimatsu Naoki, Mizumaki Masaichiro, Kawamura Naomi, Kawaguchi Saori I, Smirnova Olga, Tucker Mathew G, Watanuki Tetsu, Machida Akihiko, Takajo Shigehiro, Uwatoko Yoshiya, Shimakawa Yuichi, Takano Mikio, Azuma Masaki, Paul Attfield J
Center for Condensed Matter Sciences (CCMS), National Taiwan University, Taipei, Taiwan.
Center of Atomic Initiative for New Materials (AI-Mat), National Taiwan University, Taipei, Taiwan.
Nat Commun. 2025 Mar 5;16(1):2128. doi: 10.1038/s41467-025-57247-1.
The order or disorder of electrons is fundamental to materials properties and also provides simple analogues to the different states of matter. A charge ordered (CO) insulating state, analogous to a crystalline solid, is observed in many mixed valence materials. On heating, this melts to a charge liquid (metallic) phase, often with interesting associated physics and functions such as the Verwey transition of FeO, colossal magnetoresistances in manganites (e.g., LaCaMnO), and superconductivity in K-doped BaBiO. Here we report the observation of pressure induced charge amorphisation in a crystalline material. BiNiO has charge distribution BiBiNiO with long range order of the Bi and Bi states at ambient pressure, but adopts another, structurally crystalline, but charge glassy, insulating phase at pressures of 4-5 GPa and temperatures below 200 K, before metallization above 6 GPa. This is analogous to the much-studied pressure induced amorphisations of many crystalline materials and melting is even observed at accessible pressure/temperature. BiNiO provides fundamental insights to the study of amorphisation using charge states rather than atoms or molecules.
电子的有序或无序对于材料特性至关重要，并且还为不同的物质状态提供了简单的类比。在许多混合价材料中观察到一种电荷有序（CO）绝缘态，类似于晶体固体。加热时，这种状态会熔化为电荷液体（金属）相，通常伴随着有趣的相关物理现象和功能，例如FeO的韦尔韦转变、锰氧化物（如LaCaMnO）中的巨磁电阻以及K掺杂的BaBiO中的超导性。在此，我们报告了在一种晶体材料中观察到压力诱导的电荷非晶化现象。BiNiO在常压下具有BiBiNiO的电荷分布，其中Bi和Bi态具有长程有序，但在4 - 5 GPa的压力和低于200 K的温度下，会转变为另一种结构为晶体但电荷呈玻璃态的绝缘相，在压力高于6 GPa时才会发生金属化。这类似于对许多晶体材料进行的大量研究的压力诱导非晶化现象，甚至在可达到的压力/温度下观察到了熔化现象。BiNiO为使用电荷态而非原子或分子来研究非晶化提供了基本见解。
