Epitaxial growth of monolayer PdTe2 and patterned PtTe2 by direct tellurization of Pd and Pt surfaces

Abstract

Two-dimensional (2D) palladium ditelluride (PdTe2) and platinum ditelluride (PtTe2) are two Dirac semimetals, which have fascinating quantum properties such as superconductivity, magnetism and topological order and show the promising applications in future nanoelectronics and optoelectronics. However, the synthesis of PdTe2 and PtTe2 monolayers (MLs) is hindered by a strong interlayer coupling and orbital hybridization. In this study, we demonstrate an efficient synthesis of PdTe2 and PtTe2 MLs Large-area and high quality MLs of PdTe2 and patterned PtTe2 were epitaxially grown on the Pd(111) and Pt(111) surfaces by direct telurization in ultra-high vacuum. This was confirmed by x-ray photoelectron spectroscopy, low energy electron diffraction and scanning tunnelling microscopy. PdTe2 ML demonstrated high thermal stability showing no decomposition sign after annealing at 470 °C. A well-ordered (2 × 2) PtTe2 structure with Kagome lattice was observed on Te/Pt(111) surface following annealing at 200 °C in UHV, where the (2 × 2) pattern was formed by Te atom vacancies. PtTe2 multilayer film was prepared as well, and it demonstrated the excitation of the Dirac plasmons as measured by high-resolution electron energy loss spectroscopy. The direct tellurization offers the simple and reliable protocol for the preparation of the ML of PdTe2 and patterned PtTe2, and this opens new opportunities for quantum phenomena research and for practical optoelectronics applications.