Electron‐Doping Mottronics in Strongly Correlated Perovskite

• Published in: Advanced materials (Weinheim) 2020-02, Vol.32 (6), p.e1905060-n/a
• Main Authors: Chen, Jikun, Mao, Wei, Gao, Lei, Yan, Fengbo, Yajima, Takeaki, Chen, Nuofu, Chen, Zhizhong, Dong, Hongliang, Ge, Binghui, Zhang, Peng, Cao, Xingzhong, Wilde, Markus, Jiang, Yong, Terai, Takayuki, Shi, Jian
• Format: Article
• Language: English
• Subjects: Chemical bonds; Correlation; Crystal defects; Doping; electron correlation; Electronic devices; electronic phase transitions; Electrons; Grain boundaries; Heterostructures; Hydrogen; hydrogen doping; Occupancy; Organic chemistry; perovskite oxides; Perovskites; Positron annihilation; rare‐earth nickelates; Resistance; Transport properties
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201905060

The discovery of hydrogen‐induced electron localization and highly insulating states in d‐band electron correlated perovskites has opened a new paradigm for exploring novel electronic phases of condensed matters and applications in emerging field‐controlled electronic devices (e.g., Mottronics). Although a significant understanding of doping‐tuned transport properties of single crystalline correlated materials exists, it has remained unclear how doping‐controlled transport properties behave in the presence of planar defects. The discovery of an unexpected high‐concentration doping effect in defective regions is reported for correlated nickelates. It enables electronic conductance by tuning the Fermi‐level in Mott–Hubbard band and shaping the lower Hubbard band state into a partially filled configuration. Interface engineering and grain boundary designs are performed for HxSmNiO3/SrRuO3 heterostructures, and a Mottronic device is achieved. The interfacial aggregation of hydrogen is controlled and quantified to establish its correlation with the electrical transport properties. The chemical bonding between the incorporated hydrogen with defective SmNiO3 is further analyzed by the positron annihilation spectroscopy. The present work unveils new materials physics in correlated materials and suggests novel doping strategies for developing Mottronic and iontronic devices via hydrogen‐doping‐controlled orbital occupancy in perovskite heterostructures. The discovery of a hydrogen doping effect in correlated nickelates mediated by incoherent interfaces is reported. It increases electronic conductance by tuning the Fermi‐level in the Mott–Hubbard band. With this concept, a reconfigurable Mottronic device through defect engineering is demonstrated.