Programme

I.5 -- Invited, VCTP-49

Date: Tuesday, 30 July 2024

Time: 16:40 - 17:20

Theoretical study on high $T_c$ superconductivity in multilayer nickelates La$_$3Ni$_2$O$_7$ and La$_4$Ni$_3$O$_{10}$

Kazuhiko Kuroki

Department of Physics, Osaka University

Recent discovery of superconductivity with $T_c$ exceeding 80K in a bilayer nickelate La$_3$Ni$_2$O$_7$ under pressure has sparked a renewed interest in the field of condensed matter physics. In fact, the possibility of superconductivity in this material was theoretically discussed in 2017 by the present author. There, the importance of the $d_{3z^2-r^2}$ orbital, which exhibits large interlayer hopping, being nearly half-filled was pointed out. In the present talk, we will revisit this problem and theoretically study a realistic model taking into account the lattice structure under pressure. By applying the fluctuation exchange method to the model, we investigate the possibility of spin fluctuation mediated superconductivity, and find a result consistent with $T_c$ of 80K. Furthermore, we study the possibility of superconductivity in a trilayer nickelate La$_4$Ni$_3$O$_{10}$ in a similar manner. We find that the material can also exhibit superconductivity, which is confirmed by experiments.

Presenter: Kuroki Kazuhiko