Electronic properties and structure of indium atomic wires on Au/Si(111)
Wei-Chuan Chen1*, Jui-Cheng Lin1, Lakmal Kumara1, Chien-Cheng Kuo1
1Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
* Presenter:Wei-Chuan Chen, email:isolet0316@gmail.com
One-dimensional nanostructured materials (1D NSMs) have attracted much attention owing to their remarkable properties such as Kohn anomaly, phonon softening, and formation of charge density waves (CDW)[1]. Whilst 1D NSMs represent various types of nanostructures such as atomic wires, nanowires, nanorods, nanoribbons , and nanotubes, the electrons in these materials are subjected to strong confinement thus providing an ideal platform to study the physics of quantum confinement. In previous studies, the atomic wire-like structure observed in indium deposited on Si(111) has been reported undergoing a lattice distortion from 4 × 1 to 8 × 2 phase which is a quasi-one-dimensional CDW system below 130 K[2]. √3×√3-Au/Si(111) is a 2-dimensional electron gas (2DEG) system which provides less interaction with the substrate material thus confining the electron gas in the z-axis. As such, In/Au/Si(111) system is a 1D/2D structure while the In/Si(111) system is a 1D/3D structure. Considering all these facts, we expect some spectacular properties in 1D atomic wires of indium on √3×√3-Au/Si(111). In this study, we have observed indium atomic wires via scanning tunneling microscopy (STM) on the √3×√3-Au/Si(111) surface after depositing 0.27 ML of indium and post-annealing at 427 ℃ for 15 seconds. Scanning tunneling spectroscopy (STS) and mapping of conductance were employed to investigate the new properties and to evaluate the electronic band structure of the In/Au/Si(111) system.

[1] B. Dardel, D. Malterre, M. Grioni, P. Weibel, and Y. Baer. Phys. Rev. Lett . 67, 3144 (1991).
[2] H. Shim, S. Y. Yu, W. Lee, J. Y. Koo, and G. Lee. Appl. Phys. Lett. 94, 231901 (2009) .

Keywords: atomic wire, quasi-one-dimensional, lattice distortion