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This paper proposes, for the first time, the concept of programmable logic circuit realized with single-electron transistors (SETs). An SET having nonvolatile memory function is a key element for the programmable SET logic. The writing and erasing operations of the nonvolatile memory function make it possible to tune the phase of Coulomb oscillations. The half-period phase shift induced by the memory function makes the function of SETs complementary to that of the conventional SETs. As a result, SETs having nonvolatile memory function have the functionality of both the conventional (nMOS-like) SETs and the complementary (pMOS-like) SETs. By utilizing this fact, the function of SET circuits can be programmed with great flexibility, on the basis of the information stored by the memory functions. We have successfully fabricated SETs that operate at room temperature and observed the highest room-temperature peak-to-valley current ratio of Coulomb oscillations. The operation of the programmable SET logic is demonstrated using the room-temperature operating SETs. This is the first demonstration of room-temperature SET logic operation. The proposed programmable SET logic provides the potential for low-power, intelligent LSI chips suitable for mobile applications.

A diagnostic study of atmospheric moisture data over Saudi Arabia derived from a 43-yr National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis revealed that moisture convergence in the lower troposphere and divergence in and above the middle troposphere occurs throughout the year. Although the amount of precipitable water content in the middle troposphere is high, precipitation is less than expected over this semiarid region during a boreal summer monsoon season because of strong moisture divergence. The net tropospheric moisture flux over the arid and semiarid regions of Saudi Arabia shows seasonal and interannual variability. The seasonal variability has a strong semiannual signal with its primary peak February–April and its secondary peak June–August. This pattern is consistent with a similar semiannual signal observed in rainfall climatology. The restricted moisture supply to southwestern Saudi Arabia during summer presumably explains the lack of precipitation in other areas of the country. Winter precipitation, however, is widespread. The increased transport of net atmospheric moisture flux is higher during El Niño and positive Indian Ocean dipole (IOD) phenomena. During these events, influx across the Red Sea (west) side of Saudi Arabia increases. The net flux to the region is reduced by a slight increase of outflux across the Persian Gulf (east) side. Reanalysis data and model-sensitivity experiments show that El Niño or a concurrent positive IOD and El Niño event more strongly amplify net transport than does an independent positive IOD event. The partial-lag correlation analysis with net moisture flux from the Red Sea side shows that the positive IOD mode has a peak correlation coefficient of ∼0.5 with close to a 5-month lead and that El Niño has a peak correlation coefficient of ∼0.6 with close to a 2-month lead.

In this work, we propose a compact, physically based, analytical single-electron transistor (SET) model suitable for the design and analysis of realistic SET circuits. The model is derived on the basis of the “orthodox” theory of correlated single-electron tunneling and the steady-state master equation method. The SET inverter characteristics are successfully calculated using the model implemented in the simulation program with integrated circuit emphasis (SPICE). The hybrid circuit of SETs with metal-oxide-semiconductor field-effect transistors (MOSFETs) is also successfully simulated. By utilizing the model, it is clarified that the drain-voltage-induced shift of the gate voltage dependence of SET current reaches one-half of the drain voltage in the case of a completely symmetric SET.

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