title: Nanoscale chemical imaging by scanning tunneling microscopy assisted by synchrotron radiation.
abstract: Nanoscale chemical imaging using scanning tunneling microscopy is demonstrated with a core-level excitation of the probed element by a synchrotron radiation light. Pronounced element-specific contrasts were observed in the spatial resolution of approximately 10 nm on checkerboard-patterned Ni and Fe samples in differential photoinduced current images taken with the scanning tunneling microscopy tip under the synchrotron radiation irradiation whose photon energies are above and below the Ni (Fe) L absorption edge. The local detection of the photoinduced secondary electrons through the surface barrier lowered by the proximate tip and/or via the tunneling process probably plays an important role in achieving the high-spatial resolution.
authors.affiliation: The Institute for Solid State Physics (ISSP), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8581, Japan. okudat@issp.u-tokyo.ac.jp
authors.forename: Taichi
authors.initials: T
authors.lastname: Okuda
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Eguchi
authors.forename: Kotone
authors.initials: K
authors.lastname: Akiyama
authors.forename: Ayumi
authors.initials: A
authors.lastname: Harasawa
authors.forename: Toyohiko
authors.initials: T
authors.lastname: Kinoshita
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Masanori
authors.initials: M
authors.lastname: Kawamori
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Haruyama
authors.forename: Shinji
authors.initials: S
authors.lastname: Matsui