Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 33: Graphene: Growth, structure and substrate interaction (joint session O/HL)

O 33.3: Vortrag

Dienstag, 10. März 2026, 11:15–11:30, HSZ/0201

Defect-Driven Formation of Distinct 2D-Ag Phases at the Graphene/SiC Interface — •Sawani Datta¹, Boyang Zheng², Arpit Jain², Vibha Reddy¹, Kathrin Küster¹, Joshua A. Robinson², Vincent H. Crespi² und Ulrich Starke¹ — ¹Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — ²Pennsylvania State University, State College, USA

Intercalation of two-dimensional (2D) materials at the graphene/SiC interface is important for improving environmental stability of the intercalant and tuning graphene’s electronic properties. However, the underlying mechanisms remain complex and are still not fully understood. In this study, we show that by modifying the intercalation process, specifically through defect engineering, it is possible to selectively stabilize two distinct phases of intercalated silver (Ag). The previously established phase (Ag₁) aligns with nearly (1×1) registry of SiC [1, 2], while the second phase (Ag₂) develops a denser (3√3×3√3)R30^∘ superstructure on a (5×5) SiC unit cell, producing a 6.25×6.25 Moiré pattern with respect to graphene, as seen in the low energy diffraction (LEED) pattern [2]. Angle-resolved photoemission spectroscopy (ARPES) reveals a striking kaleidoscopic modulation of the Ag₂ and graphene bands, absent in Ag₁, along with notable differences in charge transfer between the two phases. These results demonstrate that defect-controlled, phase-selective intercalation offers a promising pathway to design and explore exotic 2D electronic states at graphene/SiC interfaces. [1] PRB 101, 201407(R) (2020). [2] arXiv:2511.07151v1 (2025).

Keywords: ARPES; Graphene; 2D-Ag