Universal Conductance Fluctuations in Metals

Observation of quantum oscillations in FIB fabricated nanowires of topological insulator (Bi2Se3)

“…Also it could be the sample response due to FIB milling which might slightly deform the material or any doping of gallium atom impurities. The slight deterioration in perfect periodicity has been also observed previously at higher fields [6] and it could be due to contributions from the Shubnikov-de Haas (SdH) oscillations of the bulk or aperiodic universal conductance fluctuations (UCFs) [21] arising from bulk states superimposing on the AB oscillations. Additionally theoretical work by Bardarson et al pointed out that conductance oscillations with magnetic flux of or depend on doping and disorder strength and indicated the motion of electrons in diffusive regime [22].…”

Localization of non-interacting electrons in thin layered disordered systems

“…It has also been investigated numerically for different lattice structures, e.g., square, honeycomb and triangular at the band center (E = 0) and away from the band center in twodimensional (2D) systems, but no extended states were found for the non-interacting and zero-field case, supporting the scaling hypothesis 10 . There have been more theoretical and experimental investigations to see the validity of the conclusions of scaling theory 5,11,12,13,14,15 , supporting the theory from a variety of numerical, experimental and analytical approaches in the absence of electron-electron interactions, magnetic field and spinorbit interactions 3,4,5,8,9,15,16 .…”

“…This subtle effect is understood as being due to the constructive interference between time-reversed paths which increases the probability of returning to the original position leading to universal conductance fluctuations 2, 3 and corrections to conductivity, whose divergence in d = 2 explains the absence of diffusion 4,5,6,7,8,9 . It has also been investigated numerically for different lattice structures, e.g., square, honeycomb and triangular at the band center (E = 0) and away from the band center in twodimensional (2D) systems, but no extended states were found for the non-interacting and zero-field case, supporting the scaling hypothesis 10 .…”

Anderson Localization of Thermal Phonons Leads to a Thermal Conductivity Maximum

“…], is Gaussian with a variance of order unity [18]. Physically this universal conductance fluctuation [34] corresponds to interference opening or closing a single conductance channel. The connection to quantized conductance channels can be made complete by identifying…”