An atomically controlled insulator-to-metal transition in iridate/manganite heterostructures

• Published in: Nature communications Vol. 15; no. 1; pp. 8427 - 8
• Main Authors: Men, Enyang, Li, Deyang, Zhang, Haiyang, Chen, Jingxin, Qiao, Zhihan, Wei, Long, Wang, Zhaosheng, Xi, Chuanying, Song, Dongsheng, Li, Yuhan, Jeen, Hyoungjeen, Chen, Kai, Zhu, Hong, Hao, Lin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28.09.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 147/137; 147/3; 639/766/119/2795; 639/766/119/544; 639/766/119/995; 639/766/119/997; Charge transfer; Correlation; Electrical resistivity; Electrons; Heterostructures; Humanities and Social Sciences; Insulation; Laboratories; Magnetoresistance; Magnetoresistivity; Metallicity; Metals; multidisciplinary; Percolation; Phase transitions; Physics; Science; Science (multidisciplinary); Temperature; Thickness; Unit cell
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-52616-8

All-insulator heterostructures with an emerging metallicity are at the forefront of material science, which typically contain at least one band insulator while it is not necessary to be. Here we show emergent phenomena in a series of all-correlated-insulator heterostructures that composed of insulating CaIrO 3 and insulating La 0.67 Sr 0.33 MnO 3 . We observed an intriguing insulator-to-metal transition, that depends delicately on the thickness of the iridate component. The simultaneous enhancements of magnetization, electric conductivity, and magnetoresistance effect indicate a percolation-type nature of the insulator-to-metal transition, with the percolation threshold can be reached at an exceptionally low volume fraction of the iridate. Such a drastic transition is induced by an interfacial charge transfer, which interestingly alters the electronic and crystalline structures of the bulk region rather than the limited ultrathin interface. We further showcased the central role of effective correlation in modulating the insulator-to-metal transition, by demonstrating that the critical thickness of iridate for triggering the metallic state can be systematically reduced down to a single unit-cell layer. Insulator-metal transitions driven by electronic correlations in oxide heterostructures have been widely studied, usually involving a correlated insulator and a band insulator. Here the authors study all-correlated-insulator heterostructures and observe a thickness-dependent insulator-metal transition.