Unveiling strong ion-electron-lattice coupling and electronic antidoping in hydrogenated perovskite nickelate.

Despite highly promising for applications in emergent electronic devices, decoding ion-electron-lattice coupling in correlated materials at atomic scale and electronic band structure remains a big challenge due to the strong and complex correlation among these degrees of freedom. Here, taking epitaxial thin film of perovskite nickelate NdNiO 3 as a model system, hydrogen ion induced giant lattice distortion and enhanced NiO 6 octahedra rotation were demonstrated, which leads to a new robust hydrogenated HNdNiO 3 phase with lattice expansion larger than 10% on a series of substrates. Moreover, under the effect of ion-electron synergistic doping, it is found that the proposed electronic antidoping, i.e., the doped electrons mainly fill the ground-state oxygen 2p holes instead of changing Ni oxidation state from Ni 3+ to Ni 2+ , dominates the metal-insulator transition. While the lattice modification with enhanced Ni-O-Ni bond rotation mainly modifies the orbital density of states near the Fermi level. Lastly, by electric-field controlled hydrogen ion intercalation and its strong coupling to the lattice and electron charge, selective micrometer-scale patterns with distinct structural and electronic states were fabricated. The results provide direct evidences for a strong ion-electron-lattice coupling in correlated physics and exhibit its potential applications in designing novel materials and devices. This article is protected by copyright. All rights reserved.