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arXiv · 2604.02191

Jahn-Teller distortion on strained La$_3$Ni$_2$O$_7$ thin films

Yuxin Wang·Zhan Wang·Fu-Chun Zhang·Kun Jiang
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Abstract

We present a systematic study of the electronic structure of strained La$_3$Ni$_2$O$_7$ thin films. We show that biaxial compressive strain mainly elongates the outer apical Ni-O bond while leaving the inner apical Ni-O bond nearly unchanged. As a result, the Jahn-Teller splitting $\Delta_{JT}$ is strongly enhanced, whereas the interlayer $d_{z^2}$ hopping $t_\perp^z$ changes only weakly. Since superconductivity is widely believed to emerge only below a critical in-plane lattice constant, our results identify the strain-enhanced $\Delta_{JT}$ as the relevant microscopic tuning parameter. Consistently, the calculated Fermi surfaces and Hall response for LaAlO$_3$ and SrLaAlO$_4$ substrates agree with ARPES and Hall measurements. Our results identify Jahn-Teller distortion as a key tuning parameter in strained La$_3$Ni$_2$O$_7$ and support its central role in optimizing superconductivity in bilayer nickelates.

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Yuxin Wang, Zhan Wang, Fu-Chun Zhang, Kun Jiang. 2026-04-02. Jahn-Teller distortion on strained La$_3$Ni$_2$O$_7$ thin films. https://arxiv.org/abs/2604.02191

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