Electric field effect on the electronic structure of 2D Y2C electride. (10th April 2018)

• Record Type: Journal Article
• Authors: Oh, Youngtek; Lee, Junsu; Park, Jongho; Kwon, Hyeokshin; Jeon, Insu; Kim, Sung Wng; Kim, Gunn; Park, Seongjun; Hwang, Sung Woo
• Is Part Of: 2D materials. Volume 5:Number 3(2018)
• Publication Date: 2018-04-10
• Subjects: electric field effect -- surface electronic structures -- yttrium hypocarbide (Y2C) electride -- scanning tunneling microscopy (STM) -- first-principles study; Graphene -- Periodicals; Materials science -- Periodicals; Nanostructured materials -- Periodicals; 620.115
• DOI: 10.1088/2053-1583/aab855
• Languages: English
• ISSNs: 2053-1583

Abstract

Abstract: Electrides are ionic compounds in which electrons confined in the interstitial spaces serve as anions and are attractive owing to their exotic physical and chemical properties in terms of their low work function and efficient charge-transfer characteristics. Depending on the topology of the anionic electrons, the surface electronic structures of electrides can be significantly altered. In particular, the electronic structures of two-dimensional (2D) electride surfaces are of interest because the localized anionic electrons at the interlayer space can be naturally exposed to cleaved surfaces. In this paper, we report the electronic structure of 2D Y2 C electride surface using scanning tunneling microscopy (STM) and first-principles calculations, which reveals that anionic electrons at a cleaved surface are absorbed by the surface and subsequently resurged onto the surface due to an applied electric field. We highlight that the estranged anionic electrons caused by the electric field occupy the slightly shifted crystallographic site compared with a bulk Y2 C electride. We also measure the work function of the Y2 C single crystal, and it shows a slightly lower value than the calculated one, which appears to be due to the electric field from the STM junction.