Dimensional crossover and band topology evolution in ultrathin semimetallic NiTe2 films

Joseph A. Hlevyack, Liang Ying Feng, Meng Kai Lin, Rovi Angelo B. Villaos, Ro Ya Liu, Peng Chen, Yao Li, Sung Kwan Mo, Feng Chuan Chuang, T. C. Chiang

研究成果: 雜誌貢獻期刊論文同行評審

3 引文 斯高帕斯(Scopus)


Nickel ditelluride (NiTe2), a recently discovered Type-II Dirac semimetal with topological Dirac fermions near the Fermi energy, is expected to exhibit strong thickness-mediated electronic tunability and intrinsic two-gap superconductivity in the single-layer limit. Realizing such intriguing phenomena requires the fabrication of ultrathin NiTe2 films and an understanding of the underlying physics that is still under debate. By conducting experimental band mappings of ultrathin films prepared with molecular beam epitaxy, we reveal spectroscopic evidence for the dimensionality crossover of single-crystalline ultrathin NiTe2 films as a function of film thickness. As the film thickness increases from one to five layers, the gap in the conical topological surface states closes. Comparisons of experimental to first-principles results also highlight difficulties in fabricating atomically smooth single-layer NiTe2 films. Our results not only provide further impetus for studying emergent phenomena in NiTe2 but also underscore the limitations of fabricating NiTe2 films for device applications.

期刊npj 2D Materials and Applications
出版狀態已出版 - 12月 2021


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