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arXiv · 2212.07134

An emergent quasi-2D metallic state derived from the Mott insulator framework

P. -C. Chiang·S. C. Lin·C. -Y. Chiang·C. -S. Ku·S. W. Huang·J. M. Lee·Y. -D. Chuang·H. J. Lin·Y. F. Liao·C. -M. Cheng·S. C. Haw·J. M. Chen·Y. -H. Chu·T. H. Do·C. W. Luo·J. -Y. Juang·K. H. Wu·Y. -W. Chang·J. -C. Yang·J. -Y. Lin
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Abstract

Recent quasi-2D systems with judicious exploitation of the atomic monolayer or few-layer architecture exhibit unprecedented physical properties that challenge the conventional wisdom on the condensed matter physics. Here we show that the infinite layer SrCuO2 (SCO), a topical cuprate Mott insulator in the bulk form, can manifest an unexpected metallic state in the quasi-2D limit when SCO is grown on TiO2-terminated SrTiO3 (STO) substrates. Hard x-ray core-level photoemission spectra demonstrate a definitive Fermi level that resembles the hole doped metal. Soft x-ray absorption spectroscopy also reveals features analogous to those of a hole doped Mott insulator. Based on these results, we conclude that the hole doping does not occur at the interfaces between SCO and STO; instead, it comes from the transient layers between the chain type and the planar type structures within the SCO slab. The present work reveals a novel metallic state in the infinite layer SCO and invites further examination to elucidate the spatial extent of this state.

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P. -C. Chiang, S. C. Lin, C. -Y. Chiang, C. -S. Ku, S. W. Huang, J. M. Lee, Y. -D. Chuang, H. J. Lin, Y. F. Liao, C. -M. Cheng, S. C. Haw, J. M. Chen, Y. -H. Chu, T. H. Do, C. W. Luo, J. -Y. Juang, K. H. Wu, Y. -W. Chang, J. -C. Yang, J. -Y. Lin. 2022-12-14. An emergent quasi-2D metallic state derived from the Mott insulator framework. https://doi.org/10.1103/physrevb.107.075104

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