Quantum transport in narrow MOSFET channels

Narrow MOSFET channels are investigated as quasi-one-dimensional electron systems containing a small number of electrons. New multiterminal devices allow resistance measurements of adjacent channel segments as small as 30 nm wide and 100 nm long. Even at high electron densities, the quantum transmission (conductance) through small segments depends strongly on electron energy (gate voltage) and magnetic field, and the behavior of adjacent segments is uncorrelated. This conductance structure saturates at low temperatures as inelastic scattering becomes negligible, and the strongest transmission "resonances" remain temperature independent as high as 20 K. The "universal conductance fluctuations" recently calculated by Lee and Stone may provide a framework for understanding these results. In larger devices, the change of scattering due to the trapping of a single electron at a particular interface trap can be isolated, and the surrounding perturbation can be spatially resolved.