Two-dimensional (2D) systems, such as graphene, transition metal chalcogenide (TMC), and transition metal oxide (TMO) hetero-interfaces, display very intriguing properties, which are not shown in their bulk form. 2D confinement significantly alters electronic wave function on top of electronic correlations with lattice, spin, and orbital. We have studied near-surface electronic properties on TMO and TMC by using in situ STM & ARPES. On PLD-grown TMO films, we have studied growth dynamics in the ultrathin SrTiO₃ and SrRuO₃ [1] and newly appeared 2D states in the hetero-interfaces (LaTiO₃/SrTiO₃,[2] and LaNiO₃/SrTiO₃[3]). On MBE-grown TMC films, we also performed ex situ ARPES studies by using Se capping method. We examined high temperature stability of few layer thick MoSe₂ films by using ellipsometry. We discuss our ARPES data on other TMC films on graphene/SiC substrates. [Acknowledgement: NRF-2014R1A1A1002868]

[1] ACS Nano 10, 5383 (2016), 'Direct Nanoscale Analysis of Temperature-Resolved Growth Behaviors of Ultrathin Perovskites on SrTiO₃', YJC, S.-H. Phark

[2] Phys. Rev. Lett. 111, 126401 (2013), ‘Layer-by-layer evolution of a two-dimensional electron gas near an oxide interface’, YJC, et al.

[3] Scientific Reports 5, 8746 (2015), 'Latent instabilities in metallic LaNiO₃ films by strain control of Fermi-surface topology', H. K. Yoo, H. D. Kim*, YJC*, et al.