Tuning of Unoccupied Band of Ir(001) by Surface Decoration

Pratyay Amrit^1*, Naoya Kawakami¹, Noriaki Takagi², Chun-Liang Lin¹, Hiroshi Ishida³, Ryuichi Arafune⁴

¹Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
³College of Humanities and Sciences, Nihon University, Tokyo, Japan
⁴Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Ibaraki, Japan

* Presenter:Pratyay Amrit, email:pratyay.sc08@nycu.edu.tw

In this study, we explored how surface modification or reconstruction impacts the electronic properties of unoccupied states on solid surfaces, focusing on the image potential states (IPSs). We have investigated the (5×1) superstructure formed with Iridium (Ir) and its effects on the IPs. To investigate the states above the Fermi level, we have measured two-photon photoemission (2PPE) spectra. Our observations revealed that the Ir(001)-(5×1) reconstructed surface exhibits a band gap in the IP band, which arises from the surface reconstruction, whereas such a band gap was absent on Ir(001)-(1×1) surface. This study offers a platform to investigate electronic properties and phenomena associated with confined electron dynamics by showing the significance of surface reconstruction in manipulating unoccupied surface states and their potential applications.

Keywords: Two-Photon Photoemission, Image Potential State, Surface Modification, Metal Surface, Iridium