Substrate and cation engineering for optimizing superconductivity in infinite-layer nickelates

Author: Christiansson, Viktor

Affiliation: TU Wien

Type: Contributed Talk

Session: Nickelates: pressure, strain, and materials tuning

Date and Time: 22.07.2026, 12:35 - 12:55

A new era of superconductivity was ushered in by the discovery of the superconducting infinite-layer (IL) nickelates [1].

In a recent experiment [2] a new record was set for the superconducting $T_c$ in the IL nickelates at ambient conditions, with a maximum close to 40 K in doped SmNiO$_2$.

Here, we use a combination of density functional theory, dynamical mean-field theory, and dynamical vertex approximation (D$\Gamma$A) calculations, which previously predicted the superconducting dome in NdNiO$_2$ later observed experimentally [3,4].

We show that the experimental Tc vs. doping dome for SmNiO$_2$ is qualitatively as well as quantitatively reproduced by our calculations [5]. Encouraged by this we go further and try to find a path towards realizing even higher $T_c$'s.

Identifying the main mechanism behind the $T_c$ increase in our calculations as an effective reduction of the interaction strength $U/t$, arising from an increase in the in-plane hopping $t$, we propose that using a series of substrates with sequentially smaller lattice constants accompanied by an appropriately chosen cation would result in substantially higher $T_c$'s.

Accordingly, our prediction is that the critical temperature in the IL nickelates still has plenty of room for improvement.

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

[2] Chow et al., Nature 642, 58 (2025)

[3] Kitatani et al., npj Quantum Materials 5, 59 (2020)

[4] Lee et al., Nature 619, 288 (2023)

[5] Christiansson & Held, arXiv:2512.20529 (2025)