  We used STM to study the tunneling spectra of FeSe0.3Te0.7 films with two
orientations of ab-planes and the connection ramp between them. We have
discovered that, using pulse laser deposition (PLD) method, the a- and b-axis
of the FeSe0.3Te0.7 film deposited on Ar-ion-milled Magnesium Oxide (MgO)
substrate are rotated 45 degree with respect to those of MgO, while the a- and
b-axis of the film grown on pristine MgO substrate are parallel to those of
MgO. With photolithography and this technique, we can prepare FeSe0.3Te0.7 film
with two kinds of orientations on the same MgO substrate, and the connection
between them forms a ramp at an angle about 25 degree to the substrate plane.
In the planar region with either 0 degree or 45 degree orientation, we have
observed tunneling spectra with a superconducting gap about 5 meV and 1.78 meV
respectively. However, a much larger gap about 18 meV has been observed in the
ramp region. Furthermore, we have also observed a small zero-bias conductance
peak (ZBCP) inside the large gap at T = 4.3K. The ZBCP becomes smaller and
disappear with increasing temperature to 7 K. The possible causes of such large
gap and the ZBCP will be discussed.
