Monday's seminar

[Cond.Matt. & Stat.Mech.Section]

CONDENSED MATTER AND  STATISTICAL PHYSICS SECTION

 
INFORMAL SEMINAR
 
 


 
 
Monday, 20 December   -    11:00 a.m.
 
 
Luigi Stasi Seminar Room -  Leonardo Bldg. - first floor
 
 
 
 
Saw-Wai HLA      (Ohio University, Athens)
 
 

"Manipulation of charge, spin and conformation  in atoms and molecules"

 

Abstract
 

Scanning tunneling microscope (STM) manipulation of single atoms and molecules on surfaces allow construction of novel quantum structures on an atom-by-atom basis and demonstration of single molecule devices on a one molecule at-a-time basis. STM is not only an instrument used to ‘see’ individual atoms by means of imaging, but also a tool used to ‘touch’ and ‘take’ atoms and molecules or to ‘hear’ their vibration by manipulations. Therefore, STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists connecting our macroscopic world to the atomic and nanoscopic world.

In our research projects, we combine a variety of STM manipulation schemes with tunneling spectroscopy techniques to investigate properties of atoms and molecules on surfaces. This talk will include our recent results and achievements; in spintronic research area, we will demonstrate that not only manipulation of magnetic atoms can be done but also imaging the direction of spin is possible by using a magnetic STM tip [1]. In superconductivity area, we will present the smallest molecular superconductor ever studied to date. Here, the finding of superconductivity in just four pairs of (BETS)2-GaCl4 molecules not only provides the possibility of investigating this phenomenon locally, but also opens potential applications in nanoelectronics [2]. In molecular spintronics area, orbital Kondo effect of TBrPP-Co molecules generated by an interfacial charge transfer process will be discussed [3]. Finally, in molecular nanomachines area, complex rotation mechanisms of Ru based doubled decker molecular rotors operated by injecting tunneling electrons from an STM tip will be presented. These experiments are innovative, and are tailored to address several critical issues covering both for fundamental understanding, and for demonstration of novel atom/molecule based nanodevices.

 

[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 (2010) 350-354.

[2]. 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 (2010) 261-265.

[3]. U.G.E. Perera, H. Kulik, V. Iancu, LGGV, Dias da Silva, S.E. Ulloa, N. Marzari, and S.-W. Hla. Spatially Extended Kondo States in Magnetic Molecules Induced by an Interfacial Charge Transfer. Phys. Rev. Lett. 105 (2010) 106601.