Epitaxial growth and atomic-scale study of type-II Dirac semimetal 1 T − NiTe 2 film

作者：Mingqiang Ren, Shuze Wang, Fanqi Meng, Lixuan Wei, Qinghua Zhang, Lin Gu, Can‐Li Song, Xu-Cun Ma, Qi‐Kun Xue · 发表于：Physical review. B./Physical review. B · 年份：2023 · DOI：10.1103/physrevb.108.235408 · 被引用次数：9 · 研究领域：Topological Materials and Phenomena、2D Materials and Applications、Graphene research and applications

By means of molecular beam epitaxy, x-ray diffraction, transmission electron microscopy, and in situ scanning tunneling microscopy, we successfully prepare type-II Dirac semimetal $1T\ensuremath{-}{\mathrm{NiTe}}_{2}$ films and investigate their surface morphology, electronic structure, and topological characteristics on the atomic scale. Atomically flat ${\mathrm{NiTe}}_{2}$ films can be readily prepared on ${\mathrm{SrTiO}}_{3}$(001) substrates at $\ensuremath{\sim}210{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. For ${\mathrm{NiTe}}_{2}$ multilayers ($\ensuremath{\sim}17$ layers), the predominant surface defect is identified as intercalated Ni atoms inside the van der Waals gap. Besides, we observe spin-splitting and resonant topological surface states near ${E}_{\text{F}}$ and at $\ensuremath{\sim}\ensuremath{-}0.65$ eV, respectively. They are suppressed at the step edges and in ultrathin monolayer and bilayer films. By exploring the quasiparticle interference, we visualize a backscattering suppression within $140\ifmmode\pm\else\textpm\fi{}40$ meV in multilayer ${\mathrm{NiTe}}_{2}$, which is associated possibly with the type-II Dirac node.