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DS: Fachverband Dünne Schichten

DS 7: 2D Materials and their Heterostructures III

DS 7.1: Talk

Wednesday, March 20, 2024, 09:30–09:45, A 053

Two-dimensional platinum chalcogenides: controlling stoichiometry for electronic applications — •Mahdi Ghorbani-Asl and Arkady Krasheninnikov — Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.

Among layered materials, platinum chalcogenides have received great attention due to their peculiar physical properties. The strong layer-dependent electronic properties cause the opening of a band gap in monolayer PtTe₂, while the system otherwise is (semi)metallic. Here we show that starting with PtTe₂ films, other compositions such as Pt₃Te₄ and Pt₂Te₂ can be obtained by a postgrowth desorption of tellurium or vapor-deposited Pt atoms. The experiments combined with DFT calculations provide insights into these transformation mechanisms and the stabilization of the new phases. The partially converted monolayer flakes exhibit PtTe₂-Pt₂Te₂ heterojunctions, which enable the formation of the in-plane semiconductor-metal interface. We further studied the electronic structure of edges and point defects in PtSe₂ monolayer where metallic 1D states with spin-polarized bands were found. In addition to stoichiometry, combining different Pt-chalcogenides in the form of vertical heterostructures provides an additional degree of engineering of materials properties. Our results showed the variation of the interlayer interaction within the moiré structure locally modulates the electronic structure of PtSe₂/PtTe₂ heterostructures.

Keywords: two-dimensional materials; platinum chalcogenides; phase stability; defects; heterostructures