Claus F. P. Kastorp: Substrate Induced Periodic Modulation of Bilayer Graphene

Dept. of Physics and Astronomy Aarhus University  Aarhus, Denmark  Bilayer graphene has recently attracted much attention and is of great interest due to both the highly correlated and widely tunable electronic properties as a function of twist angle [1], and as a potential basis system  for synthesizing diamane, a two layer diamond-like material [2].  In this experiment, we study the structural and electronic properties of bilayer graphene on Ir(111) by employing STM, XPS, Standing Wave X-ray experiments, and ARPES. The MBE synthesized bilayer graphene  acquires a graphite-like structure, meaning the separation and stacking order of the two graphene sheets is the same as found in bulk graphite. At the same time, our STM results indicate that the MBE growth is not self-limiting to two layers as reported previously [3]. We have found that the appearance of wrinkles in the graphene sheets, which are unavoidably formed during the MBE growth, play a crucial role in the multilayer graphene growth  Finally, a periodic modulation due to the presence of iridium substrate induces distinct electronic features in the band structure of our bilayer graphene that have important consequences for its application in electronic devices.  [1] Li, Guohong, et al. 2010 Nature Physics, 6.2: 109. [2] Odkhuu, D., et. al. 2013. Scientific reports, 3, p.3276. [3] Presel, F., et.al., 2018. Nanoscale, 10(16), pp.7396-7406. Claus Kastorp is currently doing his Ph.D. in experimental physics at Aarhus University on the topic of local characterization of electronic properties of Dirac materials. In particular, he works with graphene and graphene based systems. He received his B.Sc. degree in physics from Aarhus University in 2017 studying the functionalization of graphene with hydrogen on Cu(100).