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arXiv · 2610.37366

Superconductivity and local stacking polymorphism in LaNiGa2 thin films

Pengcheng Wang·Qingxiao Wang·Yameng Wu·Zixuan Huang·C. T. Lam·Zheyu Wang·Swee K. Goh·Xiaoying Xu·Yufan Li
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Abstract

LaNiGa2 has attracted considerable interest as a candidate unconventional superconductor, particularly due to its reported time-reversal symmetry breaking and nonsymmorphic crystal structure hosting symmetry-protected electronic band degeneracies. Here, we report the growth and characterization of superconducting LaNiGa2 thin films on MgO substrates by magnetron sputtering. X-ray diffraction reveals highly crystalline, (010)-oriented films with well-defined in-plane alignment and rotational twinning. Electrical transport measurements establish superconductivity with a transition temperature of approximately 1 K. Atomic-resolution transmission electron microscopy reveals local variations in crystallographic orientation and interlayer stacking, with a predominantly Cmcm structure containing minority Cmmm regions. The coexistence of these closely related structures reveals local stacking polymorphism that is difficult to distinguish using conventional X-ray diffraction. These findings establish a superconducting LaNiGa2 thin-film platform and provide new insight into the local crystal structure of a material whose electronic properties and superconducting pairing remain under active investigation.

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Pengcheng Wang, Qingxiao Wang, Yameng Wu, Zixuan Huang, C. T. Lam, Zheyu Wang, Swee K. Goh, Xiaoying Xu, Yufan Li. 2026-10-27. Superconductivity and local stacking polymorphism in LaNiGa2 thin films. https://arxiv.org/abs/2610.37366

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