AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Monday Sessions
       Session NS+NANO6-MoA

Paper NS+NANO6-MoA7
Manipulation and Inelastic Tunneling Spectroscopy Measurement of CO on Pd(110) using Low-temperature STM

Monday, October 2, 2000, 4:00 pm, Room 302

Session: Manipulation of Atoms and Molecules
Presenter: T. Komeda, Riken, Japan
Authors: T. Komeda, Riken, Japan
Y.S. Kim, Riken, Japan
M. Kawai, Riken, Japan
Correspondent: Click to Email
The ability of the scanning tunneling microcopy (STM) to manipulate a single molecule adsorbed on metal surfaces and induce local chemical reaction makes it an idealistic tool to investigate fundamentals of chemical reactions and the catalytic phenomena. In addition, the recent success of inelastic tunneling spectroscopy (IETS) to obtain chemical information by measuring its vibration state makes it more attractive. In this paper, we show the results of the manipulation and the IETS measurement by STM on carbon monoxide (CO) adsorbed on Pd(110) surface at the temperature of 4.8 K. Intriguing 1D chains of CO molecules along Pd(110) row ([-110] direction) was observed at very low-coverage region which grew to islands with local ordered structure of c(2x2). No movement of the molecule was observed during the STM measurement (tunneling current of 1nA with bias of 100 mV) for the temperature range upto 40 K. The manipulation on isolated CO molecules were done with the following method. The tip was positioned to give 0.1 nA tunneling current with 10mA substrate bias, then feedback loop was turned off. The bias between the tip and the sample was varied between -350 mV and +350 mV with the frequency of 3Hz which gives the maximum current less than 5 nA which is quite moderate for metal observation. However, this method caused the CO molecule hopped single site along [-110] direction. The driving force for the CO movement can be understood by the interaction between the electric field formed by the tip-and-sample and the dipole-moment of CO, which is considered to be very controllable method without touching between the tip and the sample. Also inelastic tunneling spectroscopy (IETS) has been carried out on an isolated CO molecule and on the CO chains. The I-V curve showed characteristic features around 250 mV.