Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 7: 2D Materials beyond graphene: Growth, structure and substrate interaction (joint session O/HL/TT)

HL 7.8: Talk

Monday, March 9, 2026, 16:45–17:00, HSZ/0204

Controlling polymorphism in the growth of 2D manganese sulfide on graphene via substrate interaction — •Max Wolfertz, Abdallah Karaka, Nicolas Georgopoulos, Oktay Güleryüz, Affan Safeer, Thomas Michely, and Jeison Fischer — II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Cologne, Germany

We investigate the epitaxial growth of single-layer manganese sulfide on graphene/Ir substrates grown via molecular beam epitaxy. Morphology, crystal structure and electronic properties are examined using scanning tunneling microscopy and - spectroscopy and low energy electron diffraction. While bulk MnS exists in the three polymorphs, α-(rock-salt structure), β-(zincblende structure), and γ-MnS (wurtzite structure), its structure in a single-layer is unknown, as fabrication using exfoliation methods cannot be applied. We find that when grown by molecular beam epitaxy on Gr/Ir substrates manganese sulfide grows in two competing phases: manganese sulfide in trigonal CuI-structure (space group P-3m1) and MnS in thin platelets of a cubic rock-salt structure (space group Fm-3m). Their in-plane lattice parameters are 4.16 Å, and 3.63 Å respectively. We show that the substrate exerts a strong influence on the phase selected. While the growth on Gr/Ir(111) results in a large share of cubic MnS, the Gr/Ir(110) substrate favors the formation of single layer trigonal manganese sulfide. Also, the use of seeding methods for avoiding loss of Mn into the bulk Ir crystals is discussed.

Keywords: manganese sulfide; substrate interaction; molecular beam epitaxy; scanning tunneling microscopy; 2D materials