%0 Journal Article
%T Observation of In-Gap States in a Two-Dimensional CrI2/NbSe2 Heterostructure.
%A Li P
%A Zhang J
%A Zhu D
%A Chen CQ
%A Yi E
%A Shen B
%A Hou Y
%A Yan Z
%A Yao DX
%A Guo D
%A Zhong D
%J Nano Lett
%V 24
%N 31
%D 2024 Aug 7
%M 39047142
%F 12.262
%R 10.1021/acs.nanolett.4c01848
%X Low-dimensional magnetic structures coupled with superconductors are promising platforms for realizing Majorana zero modes, which have potential applications in topological quantum computing. Here, we report a two-dimensional (2D) magnetic-superconducting heterostructure consisting of single-layer chromium diiodide (CrI2) on a niobium diselenide (NbSe2) superconductor. Single-layer CrI2 nanosheets, which hold antiferromagnetic (AFM) ground states by our first-principles calculations, were epitaxially grown on the layered NbSe2 substrate. Using scanning tunneling microscopy/spectroscopy, we observed robust in-gap states spatially located at the edge of the nanosheets and defect-induced zero-energy peaks inside the CrI2 nanosheets. Magnetic-flux vortices induced by an external field exhibit broken 3-fold rotational symmetry of the pristine NbSe2 superconductor, implying the efficient modulation of the interfacial superconducting states by the epitaxial CrI2 layer. A phenomenological model suggests the existence of chiral edge states in a 2D AFM-superconducting hybrid system with an even Chern number, providing a qualitatively plausible understanding for our experimental observation.