Spin-based quantum interference effects and dephasing in strongly disordered Au nanobridges

Abstract

We investigate quantum interference effects with magnetic field (magnetofingerprints) in strongly disordered Au-nanobridges. The magnetofingerprints are unconventional because they are caused by the Zeeman effect, not by the Aharonov-Bohm effect. These spin-based magnetofingerprints are equivalent to the Ericson's fluctuations (the fluctuations in electron transmission probability with electron energy). We present a model based on the Landauer-Buttiker formalism that describes the data. We show that the dephasing time τ φ (E, T ) of electrons at temperature T and energy E above the Fermi level can be obtained from the correlation magnetic field. In samples with localization length comparable to sample size, h/τ φ (E, T ) ≈ E, for E ≫ kBT , which shows that the Fermi liquid description of electron transport breaks down at length scale comparable to the localization length.

Ballistic magnetoresistance?

“…This fabrication can also be performed in UHV and cryogenic conditions. One should mention that the adequacy of such electrodes for convincing transport measurements is still a source of debate, owing to the questionable structural quality of the electrodes (due to the thin films needed to trigger a breakage) [61,62], and the possible occurrence of metallic clusters during the electromigration [63][64][65], possibly due to excessive heating during the breaking process [66,67]. Such problems limit the number of successful samples, complicating and confusing the result interpretation.…”

Magnetoresistance fluctuations in a weak disorder indium nitride nanowire

“…As shown in figure 2(b), upon increasing bias voltage three features are observed: (1) the amplitude of MR fluctuations decreases, (2) the MR patterns change with bias voltage, but certain correlation exists and (3) the symmetry survives even at high bias voltages. Increasing the bias voltage would increase the momentum of electrons participating in the transport [20], surmounting the counteracting electron-impurity scattering, leading to a monotonic decrease in the MR fluctuations. However, since the impurity configuration is not to be changed by the biasing electric field, the MR patterns should retain.…”