Emergent quasi-two-dimensional 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, Chih-Wei Luo, Jenh-Yih Juang, Kaung-Hsiung Wu, Y. W. Chang, J. C. Yang, J. Y. Lin

Research output: Contribution to journalArticlepeer-review

Abstract

Recent quasi-two-dimensional (quasi-2D) systems with judicious exploitation of the atomic monolayer or few-layer architecture exhibit unprecedented physical properties that challenge the conventional wisdom on condensed matter physics. Here we show that the infinite layer SrCuO2 (SCO), a topical cuprate Mott insulator in bulk form, can manifest an unexpected metallic state in the quasi-2D limit when SCO is grown on TiO2-terminated SrTiO3 (STO) substrates. The sheet resistance does not conform to Landau's Fermi liquid paradigm. 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 metallic state in the infinite layer SCO and invites further examination to elucidate the spatial extent of this state.

Original languageEnglish
Article number075104
JournalPhysical Review B
Volume107
Issue number7
DOIs
StatePublished - 15 Feb 2023

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