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arXiv · 2301.11550

Observation of highly anisotropic bulk dispersion and spin-polarized topological surface states in CoTe2

Atasi Chakraborty·Jun Fujii·Chia-Nung Kuo·Chin Shan Lue·Antonio Politano·Ivana Vobornik·Amit Agarwal
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Abstract

We present CoTe2 as a new type-II Dirac semimetal supporting Lorentz symmetry violating Dirac fermions in the vicinity of the Fermi energy. By combining first principle ab-initio calculations with experimental angle-resolved photo-emission spectroscopy results, we show the CoTe2 hosts a pair of type-II Dirac fermions around 90 meV above the Fermi energy. In addition to the bulk Dirac fermions, we find several topological band inversions in bulk CoTe2, which gives rise to a ladder of spin-polarized surface states over a wide range of energies. In contrast to the surface states which typically display Rashba-type in-plane spin splitting, we find that CoTe2 hosts novel out-of-plane spin polarization as well. Our work establishes CoTe2 as a potential candidate for the exploration of Dirac fermiology and applications in spintronic devices, infrared plasmonics, and ultrafast optoelectronics.

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Atasi Chakraborty, Jun Fujii, Chia-Nung Kuo, Chin Shan Lue, Antonio Politano, Ivana Vobornik, Amit Agarwal. 2023-01-27. Observation of highly anisotropic bulk dispersion and spin-polarized topological surface states in CoTe2. https://doi.org/10.1103/physrevb.107.085406

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