Dr. Philip Schädlich

Chemnitz University of Technology

Epitaxial graphene on SiC as a model playground for low-energy electron microscopy

Low-energy electron microscopy (LEEM) provides direct insight into the structural and electronic properties of layered two-dimensional (2D) materials, making it a versatile tool for investigating graphene, the pioneering 2D material. For graphene synthesis, the epitaxial growth on silicon carbide (SiC) has evolved into one of the most widely used platforms in surface science, offering a highly controllable and scalable approach, with ongoing developments in the field.

This talk will highlight how LEEM and its related techniques can be used to investigate epitaxial graphene on SiC substrates with varying surface terminations, which are accessible only via the polymer-assisted sublimation growth (PASG). Using bright-field and dark-field microscopy, we successfully identify the distinct surface terminations and observe a nuanced dependence of the graphene properties on the specific substrate termination [1,2]. These findings provide critical insights into the role of the substrate in tailoring the electronic properties of graphene.

Furthermore, epitaxial graphene serves as a unique experimental platform for the synthesis of otherwise unstable 2D phases of elements by intercalation. Among these, heavy metals such as lead and bismuth are of particular interest due to their strong intrinsic spin-orbit coupling and their potential to induce strong correlation effects in graphene's 2D electron gas. I will discuss how LEEM helps to understand the formation and structure of these intercalation phases [3, 4].

[1] D.M. Pakdehi, P. Schädlich, T.T.N. Nguyen, A.A. Zahkharov, S. Wundrack, E. Najafidehaghani, F. Speck, K. Pierz, Th. Seyller, C. Tegenkamp, H.W. Schumacher, Adv. Funct. Mater. 30, 2004695 (2020).

[2] A. Sinterhauf, G.A. Traeger, D.M. Pakdehi, P. Schädlich, P. Willke, F. Speck, Th. Seyller, C. Tegenkamp, K. Pierz, H.W. Schumacher, M. Wenderoth, Nat. Commun. 11, 555 (2020).

[3] F. Schölzel, P. Richter, A.D.P. Unigarro, S. Wolff, H. Schwarz, A. Schütze, N. Rösch, S. Gemming, Th. Seyller, P. Schädlich, Small Struct. 6, 2400338 (2025).

[4] S. Wolff, M. Hutter, P. Schädlich, H. Yin, M. Stettner, S. Wenzel, F.S. Tautz, F.C. Bocquet, Th. Seyller, C. Kumpf, New J. Phys. 26, 103009 (2024).