Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
TT 20.6: Vortrag
Dienstag, 17. März 2020, 12:15–12:30, HSZ 03
Topotactic hydrogen in nickelate superconductors and akin infinite-layer oxides ABO2 — •Karsten Held1, Liang Si1,2, Wen Xiao2, Josef Kaufmann1, Yi Lu3, Jan M. Tomczak1, and Zhicheng Zhong2 — 1Institute for Solid State Physics, TU Wien, Austria — 2Chinese Academy of Science NIMTE, Ningbo, China — 3Institute for Theoretical Physics, Heidelberg University, Germany
The seminal work by Li et al.  opens the door wide to the nickelate age of superconductivity. But it appears to be most difficult to reproduce. Since the chemical reduction of ABO3 (A: rare earth; B transition metal) with CaH2 may result in both, ABO2 and ABO2H, we calculate  the topotactic H binding energy by density functional theory (DFT). We find intercalating H to be energetically favorable for LaNiO2 and NdNiO2 but not for Sr-doped NdNiO2.
This topotactical hydrogen turns the electronic structure upside down. Our DFT+dynamical mean field theory calculations show  that 3d9 LaNiO2 is similar to (doped) cuprates, whereas 3d8 LaNiO2H is a two-orbital Mott insulator, similar to LaNiO3|LaAlO3 heterostructures prior to engineering their bandstructure to a cuprate-like one . Topotactic H might hence explain why some nickelates are superconducting and others are not.
 D. Li et al., Nature 572, 624 (2019).
 L. Si, W. Xiao, J. Kaufmann, J.M. Tomczak, Y. Lu, Z. Zhong, K. Held, arXiv:1911.06917.
 P. Hansmann, X. Yang, A. Toschi, G. Khaliullin, O. K. Andersen, and K. Held, Phys. Rev. Lett. 103, 016401 (2009).