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DOE OSTI · 2229876

Emergent quasi-two-dimensional metallic state derived from the Mott-insulator framework

Chiang, P. -C.·Lin, S. C.·Chiang, C. -Y.·Ku, C. -S.·Huang, Shih W.·Lee, J. M.·Chuang, Y. -D.·Lin, H. J.·Liao, Y. F.·Cheng, C. -M.·Haw, S. C.·Chen, J. M.·Chu, Y. -H.·Do, T. H.·Luo, C. -W.·Juang, J. -Y.·Wu, K. H.·Chang, Y. -W.·Yang, J. -C.·Lin, J. -Y.
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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 SrCuO 2 (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 TiO 2 -terminated SrTiO 3 (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. In conclusion, the present work reveals a metallic state in the infinite layer SCO and invites further examination to elucidate the spatial extent of this state.

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75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITYCondensed Matter, Materials & Applied PhysicsElectrical conductivityMott insulatorsUltrathin films

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Chiang, P. -C., Lin, S. C., Chiang, C. -Y., Ku, C. -S., Huang, Shih W., Lee, J. M., Chuang, Y. -D., Lin, H. J., Liao, Y. F., Cheng, C. -M., Haw, S. C., Chen, J. M., Chu, Y. -H., Do, T. H., Luo, C. -W., Juang, J. -Y., Wu, K. H., Chang, Y. -W., Yang, J. -C., Lin, J. -Y.. 2023-02-02. Emergent quasi-two-dimensional metallic state derived from the Mott-insulator framework. https://doi.org/10.1103/physrevb.107.075104

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