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Manipulation of Molecular Charge Density Waves and Molecular Transport Systems

Latt, Kyaw Zin
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1557418915977344

Abstract Details

2019, Doctor of Philosophy (PhD), Ohio University, Physics and Astronomy (Arts and Sciences).
This dissertation explores the manipulation of charges in a 2-D self-assembled organic molecular cluster and the manipulation of a molecular machine, a nanocar, using a low temperature ultrahigh vacuum scanning tunneling microscopy on a metal substrate. A donor-acceptor type organic charge transfer salt, α-(BEDT-TTF)2-I3 or α-ET2-I3 (BEDT-TTF=ET=Bis(ethylenedithio)tetrathiafulvalene), is thermally deposited onto Ag(111) substrate for different coverages. The scanning tunneling microscope (STM) investigation reveals different molecular assemblies in the first layer clusters, from partially ordered to ordered arrangements, at the sub-monolayer regime. At slightly higher coverages, the formation of charge density wave (CDW) is observed for the first time at both 5K and 80K substrate temperatures on 2 and 3 monolayer thick molecular islands. The nature of CDW is studied using scanning tunneling spectroscopy (STS) and density functional theory calculations. Furthermore, the observed CDW in the molecular islands is manipulated by using inelastic electron tunneling (IET) and the electric field supplied from the scanning tunneling microscope (STM) tip. The CDW patterns can be destroyed above 1.6V bias however, the same CDW pattern can be reinstated when the STM images are acquired by reducing the bias voltage. Using IET manipulation, the bi-stable deformation nature of CDW modulation is explored, and switching between two CDW states as a function of electric field and current densities are statistically analyzed. The molecular nanomachine, the nanocar, formed by using supermolecular [5]pseudorotaxane as an H-shaped frame and four Cucurbit[7]uril (CB[7]) as wheels, is thermally deposited on Au(111) substrate. The STM tip is used to extract a wheel from a nanocar to confirm its integrity upon deposition onto the surface, and to investigate the structure of the wheel. The chassis of the nanocar includes positive charges, which are used for the controlled driving of the nanocar using the STM tip induced electric field manipulation. The threshold electric field required to manipulate is also determined and found to be ~800mV.
Saw-Wai Hla (Advisor)
Arthur Smith (Committee Member)
Sergio Ulloa (Committee Member)
Eric Stinaff (Committee Member)
Hugh Richardson (Committee Member)
101 p.
Condensed Matter Physics; Molecular Physics; Nanoscience; Physics; Scientific Imaging
STM; CDW; Charge density wave; ET2-I3; Molecular machine; Nanocar;

Recommended Citations

Citations

  • Latt, K. Z. (2019). Manipulation of Molecular Charge Density Waves and Molecular Transport Systems [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1557418915977344

    APA Style (7th edition)

  • Latt, Kyaw Zin. Manipulation of Molecular Charge Density Waves and Molecular Transport Systems. 2019. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1557418915977344.

    MLA Style (8th edition)

  • Latt, Kyaw Zin. "Manipulation of Molecular Charge Density Waves and Molecular Transport Systems." Doctoral dissertation, Ohio University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1557418915977344

    Chicago Manual of Style (17th edition)

ohiou1557418915977344
© 2019, all rights reserved.
This open access ETD is published by Ohio University and OhioLINK.