Studies in layered high-temperature superconductors with a low-temperature scanning tunnelling microscope
Abstract
In this thesis, pulsed laser deposited films of $\rm YBa\sb2Cu\sb3O\sb{7-\delta}$ (YBaCuO) have been successfully probed with scanning tunneling spectroscopy. Tunneling conductance data (G(eV) = dI/dV) obtained from these experiments has been carefully analyzed and has revealed a fine structure rich in detail. This structure has been compared to a theoretical model of the expected tunneling conductance based on a band structure calculation of YBaCuO by Tachiki et. al. The close agreement between this model and our data confirms that we have observed effects due to the detailed structure of the electronic density of states in YBaCuO. The agreement between experiment and theory provides insight into the factors influencing the tunneling and transport of current in high Tc materials. Further experiments investigating single electron tunneling phenomena in a thallium based high temperature superconductor are discussed in Chapter 7. The insight gained from the studies on thallium based superconductors supports the c-axis current transport model implicit in the tunneling model used to fit the data in Chapter 6 and further emphasizes the importance of understanding the effects of a layered structure upon the electronic and transport properties in such materials.
Degree
Ph.D.
Advisors
Reifenberger, Purdue University.
Subject Area
Condensation
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.