Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 32: 2D Materials 2 (joint session DS/HL)

HL 32.1: Talk

Wednesday, March 11, 2026, 15:00–15:15, REC/C213

Engineering at the Thinnest Scale: Insights into the Stability of 2D GaN on Liquid Metal Catalysts — •Tomoko Yokaichiya, Karsten Reuter, and Hendrik H. Heenen — Fritz-Haber-Institut der MPG, Berlin

Hexagonal GaN (h-GaN), theorized to be metastable when confined to only a few nanometers, stands out as a promising wide-bandgap semiconductor for next-generation nanoelectronics. Although early studies report that h-GaN can be synthesized using e.g. liquid metal catalysts, its definitive experimental identification is challenging. This difficulty arises from a structural ambiguity due to possible defects, multilayer-stacking variations, and competing polymorphs of h-GaN's characteristic honeycomb structure, as predicted by pioneering, yet simplified electronic-structure studies. In this work, we use density functional theory alongside large-scale atomistic simulations based on machine-learned interatomic potentials to re-assess the stability of h-GaN at finite temperatures and in the presence of a liquid metal substrate. We systematically investigate the structural and electronic properties of h-GaN, examining how they evolve with layer thickness and possible structural variations. Furthermore, we analyze its thermodynamic competition with bulk wurtzite GaN and alternative thin-film polymorphs, including a previously suggested haeckelite phase. Our results reveal that h-GaN exists within a delicate stability window. Based on these insights, we propose key signatures to guide experimental detection and outline whether h-GaN may become synthesizable as a feasible 2D semiconductor.

Keywords: Semiconductor; Hexagonal GaN; Phase stability; Atomistic simulation; MLIP