The role of π-blocking hydride ligands in a pressure-induced insulator-to-metal phase transition in SrVO2H. Issue 1 (December 2017)

• Record Type: Journal Article
• Authors: Yamamoto, Takafumi; Zeng, Dihao; Kawakami, Takateru; Arcisauskaite, Vaida; Yata, Kanami; Patino, Midori; Izumo, Nana; McGrady, John; Kageyama, Hiroshi; Hayward, Michael
• Is Part Of: Nature communications. Volume 8:Issue 1(2017)
• Page Start: 1
• Page End: 7
• Publication Date: 2017-12
• Subjects: Biology -- Periodicals; Physical sciences -- Periodicals; 505
• DOI: 10.1038/s41467-017-01301-0
• Languages: English
• ISSNs: 2041-1723

Abstract

Abstract Transition-metal oxyhydrides are of considerable current interest due to the unique features of the hydride anion, most notably the absence of valencep orbitals. This feature distinguishes hydrides from all other anions, and gives rise to unprecedented properties in this new class of materials. Here we show via a high-pressure study of anion-ordered strontium vanadium oxyhydride SrVO2 H that H− is extraordinarily compressible, and that pressure drives a transition from a Mott insulator to a metal at ~ 50 GPa. Density functional theory suggests that the band gap in the insulating state is reduced by pressure as a result of increased dispersion in theab -plane due to enhanced Vdπ -Opπ -Vdπ overlap. Remarkably, dispersion alongc is limited by the orthogonal Vdπ -H1s -Vdπ arrangement despite the greaterc -axis compressibility, suggesting that the hydride anions act as π-blockers. The wider family of oxyhydrides may therefore give access to dimensionally reduced structures with novel electronic properties. Incorporating hydride anions into transition metal oxides can dramatically affect their structural and electronic properties. Here the authors reveal a pressure-induced insulator-to-metal transition in SrVO2 H and show that the compressibility of hydride anions without π-symmetry valence orbitals causes them to act as π-blockers.