The Anthony J Leggett Institute for Condensed Matter Special Theory Seminar, Elbio Dagotto (University of Tennessee and Oak Ridge National Laboratory), "The new era of Ni-oxide high-Tc superconductors"
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- Physics - The Anthony J Leggett Institute for Condensed Matter Theory
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- Elbio Dagotto
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- Physics - The Anthony J Leggett Institute for Condensed Matter Theory Seminar
Abstract: In 2023, shocking news spread that a Ni-based bilayer oxide superconductor had been found with a Tc of 80 K, starting the current frenzy of Ni high-Tc superconductivity [1]. The chemical formula is La3Ni2O7 (LNO). Although superconductivity in LNO was originally achieved at high pressure, compressive strain has been recently shown to produce thin films that superconduct at ambient pressure with Tc ~63K [2]. My presentation will start with a quick review of the precursors of the present frenzy using Ni-based thin films of the infinite-layer phase [3]. Superconductivity in trilayers [4] will also be discussed, time allowing. Theoretical developments by several groups have unveiled a Fermi surface where a distinct feature emerges: a so-called gamma-pocket at k=(pi,pi) which appears to be one-to-one linked to superconductivity [5]. In addition to this feature, several other differences with high-Tc cuprates were unveiled, such as the formation of “dimers” in between the two NiO2 planes of the bilayer, as well as dominant “magnetic stripe” tendencies, within the random phase approximation, that only partially have been confirmed experimentally yet. Although I will focus on only a handful of experimental and theoretical results, the publications by my group contain vast literature that interested readers can consult for a more detailed view of the subject. The field of Ni-oxide superconductivity is rapidly evolving, and surprises appear in the arXiv on a weekly basis, rendering this area exciting and one of the hottest topics of research in present day Condensed Matter Physics.
[1] H. Sun, …, and M. Wang, Nature 621, 493 (2023). N. Wang, …, and J. Cheng, Nature 634, 579 (2024).
[2] E.K. Ko et al. Nature 638, 935 (2025); G. Zhou et al. Nature 640, 641 (2025); Y. Tarn et al., arXiv:2512.04708
[3] D. Li, …, and H. Hwang, Nature 572, 624 (2019).
[4] Y. Zhu, …, and J. Zhao, Nature 631, 531 (2024); Y. Zhang et al., PRL 133, 136001 (2024).
[5] Y. Zhang et al., Nat Commun 15, 2470 (2024) and references therein. See also Y. Zhang et al., PRB 108, L180510 (2023); PRB 108, 165141 (2023); L.-F. Lin et al., PRB 110, 195135 (2024); Y. Zhang et al., PRB 109, 045151 (2024).
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Zoom Link: https://illinois.zoom.us/my/icmt.seminar?pwd=ZU1KbnBLeXZLUmJKc0oyU205cDNDdz09
Meeting ID: 791 382 8328
Password: 106237