Nanowires based on InN are interesting because of their large surface conductivity and their low energy band gap. For nanoscaled devices operated at low temperatures electron interference effects can largely affect the transport properties. Typical phenomena are universal conductance fluctuations or weak localization. The characteristic fluctuation pattern observed in the conductance was employed to obtain information on phase-coherent transport. The conductance fluctuations were measured at low temperatures as a function of the gate voltage at fixed magnetic fields. By analyzing the root mean square and the correlation field of the conductance fluctuations at various temperatures, the phase-coherence length was determined. From the conductance traces as a function of gate voltage the variance of the conductance var(G) was determined at different magnetic fields. The largest variance was found close to zero magnetic field while at finite magnetic fields var(G) is reduced to almost half value. This reduction can be explained by the broken time-reversal symmetry in the presence of a magnetic field.
1 Jul 2009
Verhandlungen der Deutschen Physikalischen Gesellschaft