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arXiv · 2112.01677

Microscopic Theory of Superconducting Phase Diagram in Infinite-Layer Nickelates

T. Y. Xie·Z. Liu·Chao Cao·Z. F. Wang·J. L. Yang·W. Zhu
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Abstract

Since the discovery of superconductivity in infinite-layer nickelates RNiO$_2$ (R=La, Pr, Nd), great research efforts have been paid to unveil its underlying superconducting mechanism. However, the physical origin of the intriguing hole-doped superconductivity phase diagram, characterized by a superconductivity dome sandwiched between two weak insulators, is still unclear. Here, we present a microscopic theory for electronic structure of nickelates from a fundamental model-based perspective. We found that the appearance of weak insulator phase in lightly and heavily hole-doped regime is dominated by Mottness and Hundness, respectively, exhibiting a unique orbital-selective doping originated from the competition of Hund interaction and crystal field splitting. Moreover, the superconducting phase can also be created in the "mixed" transition regime between Mott-insulator and Hund-induced insulator, exactly reproducing the experimentally observed superconducting phase diagram. Our findings not only demonstrate the orbital-dependent strong-correlation physics in Ni 3$d$ states, but also provide a unified understanding of superconducting phase diagram in hole-doped infinite-layer nickelates, which are distinct from the well-established paradigms in cuprates and iron pnictides.

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T. Y. Xie, Z. Liu, Chao Cao, Z. F. Wang, J. L. Yang, W. Zhu. 2021-12-03. Microscopic Theory of Superconducting Phase Diagram in Infinite-Layer Nickelates. https://doi.org/10.1103/physrevb.106.035111

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