SKM 2023 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 44: Focus Session: Superconducting Nickelates I
TT 44.6: Vortrag
Donnerstag, 30. März 2023, 12:15–12:30, HSZ 03
Nickelate superconductors: One-band Hubbard model plus decoupled A pocket picture — •Karsten Held1, Motoharu Kitatani2, Liang Si1,3, and Paul Worm1 — 1Institute for Solid State Physics, TU Wien, Austria — 2University of Hyogo , Japan — 3Northwest University, Xi’an, China
At first glance, nickelate superconductors appear to be more complicated than their cuprate peers. Based on density functional theory (DFT) plus dynamical mean-field theory (DMFT) we however arrived at a picture that the physics of nickleate superconductors is dominated by the Ni dx2−y2-band and the pockets are, in many respects, merely passive bystanders [1]. Other groups have argued instead for the importance of the Ni dz2-band based, e.g., on self-interaction corrected (sic)DFT+DMFT [2].
Taken the premise of a dx2−y2-band Hubbard model description, we have predicted the phase diagram, superconducting critical temperature Tc vs. doping x [1]. Later experiments synthesizing high-quality films are in excellent qualitative and even quantitative agreement [3], as is the resonant inelastic x-ray (RIXS) spectrum. Also the pentalayer nickelate superconductor which has no pockets in DFT+DMFT and the increase Tc with pressure nicely match this picture [4].
[1] M. Kitatani et al., npj Quantum Materials 5, 59 (2020)
[2] F. Lechermann, Phys. Rev. B 101, 081110 (2020);
A. Kreisel et al., Phys. Rev. Lett. 129, 077002 (2022)
[3] K. Lee et al., arXiv:2203.02580
[4] P. Worm et al., Phys. Rev. Mater. 6, L091801 (2022)