Bulk Dirac cone and highly anisotropic electronic structure of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Ni</mml:mi><mml:msub><mml:mi>Te</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Munisa Nurmamat, С. В. Еремеев, Xiaoxiao Wang, Tomoki Yoshikawa, Takashi Kono, Masaaki Kakoki, Takayuki Muro, Qi Jiang, Zhipeng Sun, Mao Ye, A. Kimura
Abstract
Transition-metal dichalcogenides (TMDCs) hosting type-II Dirac fermions have attracted a great deal of research interest owing to their rich application capabilities. Here, we have systematically investigated the bulk and surface electronic structures of type-II Dirac semimetal $\mathrm{Ni}{\mathrm{Te}}_{2}$ by means of angle-resolved photoelectron spectroscopy (ARPES) combined with first-principles calculations. As a result, a bulk Dirac point located 150 meV below the Fermi energy is directly observed by using bulk-sensitive soft x-ray ARPES. Moreover, the measured Fermi surfaces of $\mathrm{Ni}{\mathrm{Te}}_{2}$ are found to be strongly anisotropic. The first-principles calculations, which match remarkably well with the experimental results, show that the energy position of the Dirac point crucially depends on a small variation of the structural parameters. Our work establishes $\mathrm{Ni}{\mathrm{Te}}_{2}$ as an ideal platform for further investigating the anisotropic magnetotransport associated with type-II Dirac fermions in TMDCs and paves the way for prospective applications.