Abstract
The significant reduction in the conductance of a tunneling system near zero bias voltage is termed the Zero Bias Feature (ZBF). A ³He cryostat has been modified to incorporate a Self-Assembling Tunnel Junction (SATJ), capable of performing Inelastic Tunneling Spectroscopy (IETS). In a SATJ, a barrier gas is deposited in situ between two metal wires that can be remotely manipulated by a magnetic field, to vary the junction conductance. The ZBF is studied for platinum/neon/platinum tunnel junctions. A novel method of carrying large currents into the cryostat by means of a flexible vapor-cooled magnet lead is discussed. The cryostat is proven to operate well over a wide range of high temperatures (1.5K to 32.3K), but insufficient for low temperature use (to 0.3K). Data has been analyzed using the 2-Channel Kondo model to test whether electron scattering from nearly degenerate two-level defects are responsible for the ZBFs in these systems. Results indicate partial disagreement with theory, in particular the non-scaling behavior of ZBF parameters with temperature. However, future improvements to the cryostat and additional measurements will help resolve these issues.
Savitski, Stephen Ronald (2000). Temperature study of Zero Bias Features using self-assembling tunnel junctions. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2000 -THESIS -S286.