We present a systematic study of the electronic structure of strained La3Ni2O7 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 ΔJT is strongly enhanced, whereas the interlayer dz2 hopping t⊥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 ΔJT as the relevant microscopic tuning parameter. Consistently, the calculated Fermi surfaces and Hall response for LaAlO3 and SrLaAlO4 substrates agree with ARPES and Hall measurements. Our results identify Jahn-Teller distortion as a key tuning parameter in strained La3Ni2O7 and support its central role in optimizing superconductivity in bilayer nickelates.
@article{arxiv.2604.02191,
title = {Jahn-Teller distortion on strained La$_3$Ni$_2$O$_7$ thin films},
author = {Yuxin Wang and Zhan Wang and Fu-Chun Zhang and Kun Jiang},
journal= {arXiv preprint arXiv:2604.02191},
year = {2026}
}