Electrical characterization of MgO tunnel barriers grown on InAs (001) epilayers

Abstract

The authors examine the electrical properties of ultrathin MgO barriers grown on ͑001͒ InAs epilayers and the dependence on InAs surface pretreatment and growth conditions. Pretreatment improves the yield of tunnel junctions and changes the roughness of the interface between oxide and semiconductor. Electrical characterization confirms that tunnel barriers with appropriate values of interface resistance for efficient spin injection/detection have been achieved. Using the Rowell criteria and various tunneling models, the authors show that single step tunneling occurs above 150 K. Incorporating a thermal smearing model suggests that tunneling is the dominant transport process down to 10 K.

Normal-state conductance used to probe superconducting tunnel junctions for quantum computing

“…However, as the temperature is lowered, the parabolic behavior gradually transforms to Vshaped curves, as depicted in the figure. The gradual transition from parabolic to linear behavior, which is typical of the common ZBA, can be seen more clearly in figure 3(b), where the curves are all normalized to the values around ±0.15 V. Such a transition from parabolicity to sharp ZBA was obtained previously in other systems [14,32], and is regarded as a sign of electronic disorder at the interface. In comparison, although figure 2(a) might also give the impression of a similar ZBA, even for the e-Re/e-AlO/p-Al junction, the inset of figure 2(a) shows that there is in fact a flat, albeit asymmetric, region right around zero voltage.…”