Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 22: Unconventional Superconductors

TT 22.8: Hauptvortrag

Mittwoch, 7. September 2022, 17:15–17:45, H10

Role of the film geometry in the electronic reconstruction of infinite-layer nickelates on SrTiO₃(001) — •Benjamin Geisler — Fakultät für Physik, Universität Duisburg-Essen

The recent discovery of superconductivity in infinite-layer NdNiO₂ films on SrTiO₃(001) has sparked significant interest [1]. However, details of the physical mechanism behind this observation remained so far elusive, since in contrast to the thin films [2] bulk NdNiO₂ shows neither superconductivity nor the antiferromagnetic interactions characteristic of high-T_c cuprates.

First-principles simulations unravel the key role of the interface: Polarity mismatch drives a surprising electronic reconstruction that results in the emergence of a correlated two-dimensional electron gas (2DEG) in the SrTiO₃(001) substrate. The concomitant depletion of the self-doping Nd 5d states renders infinite-layer nickelates close to cuprate superconductors [3,4]. Recent work identifies an unexpected interface composition that completely quenches the 2DEG, but preserves the electronic reconstruction in the nickelate film [5]. This supports the notion of nickelate superconductivity as novel quantum phase, induced in film geometry by electronic reconstruction.

[1] D. Li et al., Nature 572, 624 (2019)

[2] H. Lu et al., Science 373, 213 (2021)

[3] B. Geisler and R. Pentcheva, PRB 102, 020502(R) (2020)

[4] B. Geisler and R. Pentcheva, Phys. Rev. Res. 3, 013261 (2021)

[5] B. H. Goodge, B. Geisler, K. Lee, M. Osada, B. Y. Wang, D. Li, H. Y. Hwang, R. Pentcheva, L. F. Kourkoutis, arXiv:2201.03613