Argonne National Laboratory

Upcoming Events

Frontiers of STM Manipulations: Imaging Atomic Spin to Operating Nanomachines

Materials Science Colloquium
Saw Wai Hla, (CNM) and Ohio University
September 26, 2013 11:00AM to 12:00PM
Building 212, Room A157
We combine a variety of scanning tunneling microscope (STM) manipulation schemes with tunneling spectroscopy techniques to image and manipulate properties of atoms and molecules on surfaces. This talk will highlight recent advances achieved by manipulation at atomic and molecular scale [1-4]. In spintronic area, we will present imaging and manipulation of atomic spin using a spin-polarized STM tip [1], and the spin fiction phenomenon at the atomic scale [2]. In nanoscale superconductivity area, donor-acceptor type charge transfer based molecular superconducting system will be discussed. Here, the finding of superconductivity in just four pairs of (BETS)2-GaCl4 molecules opens the possibility of investigating superconducting phenomena locally [3]. In molecular machine area, we will present controlled rotation of a stand-alone multi-component molecular motor operated by injecting tunneling electrons from an STM tip. By selectively exciting different rotator arms of these molecular motors, controlled rotations into both, clockwise and counterclockwise directions have been achieved [4]. These innovative experiments are tailored to address several critical issues covering fundamental understanding as well as demonstration of novel atom/molecule based devices on materials surfaces.

[1] D. Serrate, P. Ferriani, Y. Yoshida, S.-W. Hla, M. Menzel, K. von Bergmann, S. Heinze, A. Kubetzka, and R. Wiesendanger. Imaging and manipulating the spin direction of individual atoms. Nature Nanotechnology 5, 350-354 (2010).

[2] B. Wolter, Y. Yoshida, A. Kubetzka, S.-W. Hla, K. von Bergmann and R. Wiesendanger. Spin friction observed on the atomic scale. Phys. Rev. Lett. 109, 116102 (2012).

[3] K. Clark, A. Hassanien, S. Khan, K.-F. Braun, H. Tanaka, and S.-W. Hla. Superconductivity in just four pairs of (BETS)2- GaCl4 molecules. Nature Nanotechnology 5, 261-265 (2010).

[4] U.G.E. Perera, F. Ample, H. Kersell, Y. Zhang, G. Vives, J. Echeverria, M. Grisolia, G. Rapenne, C. Joachim, & S.-W. Hla. Controlled clockwise and anticlockwise rotational switching of a molecular motor. Nature Nanotechnology 8, 46-51 (2013).