Highly Organized Epitaxy of Dirac Semimetallic PtTe2 Crystals with Extrahigh Conductivity and Visible Surface Plasmons at Edges.

Platinum telluride (PtTe2), a member of metallic noble-transition-metal dichalcogenides (MNTMDs), has emerged as an indispensable candidate for superconducting, magnetic, and other electronic phase engineering, as well as optic applications. Herein, we report the van der Waals epitaxy of high-crystalline few-layer PtTe2 crystals on inert mica. Density functional theory calculations are used to illustrate a type-II Dirac cone along the Γ-A direction in the PtTe2 crystal. Impressively, the PtTe2 devices exhibit an extra-high electrical conductivity of 107 S m-1, 1000 times higher than that of metallic 1T MoS2. Meanwhile, the magnetoresistance effect at low temperatures reaches 800% in a field of 9.0 T. Furthermore, near-field nanooptical properties are assessed on PtTe2. Considering the subwavelength effect, the plasmonic wavelength λp ≈ 200 nm of 1T PtTe2 is obtained and the carrier concentration calculated from λp is about 1.22 × 1015 cm-2, which is 100-fold higher than that of MoTe2 in the previous reports. Therefore, our work demonstrates the growth of MNTMDs and provides insights into the plasmonic properties of 2D metallic telluride compounds.