|Title :||Nano Science Seminar : "Synchrotron X-ray Scanning Tunneling Microscopy"|
11:00 AM - 0:00 PM
|Place :||Meeting Room 1 (A636), 6th Floor, ISSP|
|Lecturer :||Dr. Volker Rose|
|Affiliation :||Advanced Photon Source & Center for Nanoscale Materials, Argonne National Laboratory|
|Summary :||The combination of the high spatial resolution of scanning tunneling microscopy with the chemical and magnetic contrast provided by synchrotron X-rays has the potential to allow a unique characterization of advanced materials.  While the scanning probe provides the high spatial resolution, synchrotron X-rays that produce photo-excitations of core electrons add chemical and magnetic contrast. The x-ray excitations result in tip currents that are superimposed onto conventional tunneling currents.  We have developed an easy-to-implement filter circuit that can separate the x-ray induced currents from conventional tunneling currents, thereby allowing simultaneous measurements of topography and chemical contrasts.  Critical for high spatial resolution are insulator-coated "smart tips" with small conducting apex. Such tips drastically reduce the background of photoejected electrons by reducing the detection area to the tip apex.
In this talk, we will discuss the physical principles of synchrotron x-ray scanning tunneling microscopy (SXSTM) as well as the implementation of this emerging technique at the Advanced Photon Source at Argonne National Laboratory. 
 V. Rose, J.W. Freeland, S.K. Streiffer, "New Capabilities at the Interface of X-rays and Scanning Tunneling Microscopy", in Scanning Probe Microscopy of Functional Materials: Nanoscale Imaging and Spectroscopy, S.V. Kalinin, A. Gruverman, (Eds.), Springer, New York (2011), pg 405-432.
 Volker Rose, Kangkang Wang, TeYu Chien, Jon Hiller, Daniel Rosenmann, John W. Freeland, Curt Preissner, Saw-Wai Hla, Adv. Funct. Mater. 23, 2646 (2013).
 Kangkang Wang, Daniel Rosenmann, Martin Holt, Robert Winarski, Saw-Wai Hla, and Volker Rose, Rev. Sci. Instrum. 84, 063704 (2013).
 M.L. Cummings, T.Y. Chien, C. Preissner, V. Madhavan, D. Diesing, M. Bode, J.W.Freeland, and V. Rose, Ultramicroscopy 112, 22 (2012).
|Committee Chair :|| (ext.63325)
e-mail: hasegawa :at: issp.u-tokyo.ac.jp