Universal conductance fluctuations

Universal conductance fluctuations (UCF) in mesoscopic physics is a phenomenon encountered in electrical transport experiments in mesoscopic species. The measured electrical conductance will vary from sample to sample, mainly due to inhomogeneous scattering sites. Fluctuations originate from coherence effects for electronic wavefunctions and thus the phase-coherence length $\backslash textstyle\; l\_\backslash phi$ needs be larger than the momentum relaxation length $\backslash textstyle\; l\_m$. UCF is more profound when electrical transport is in weak localization regime.

Many factors will influence the amplitude of UCF. At zero temperature without decoherence, the UCF is influenced by mainly two factors, the symmetry and the shape of the sample. Recently, a third key factor, anisotropy of Fermi surface, is also found to fundamentally influence the amplitude of UCF.{{Cite journal|last1=Hu|first1=Yayun|last2=Liu|first2=Haiwen|last3=Jiang|first3=Hua|last4=Xie|first4=X. C.|date=2017-10-05|title=Numerical study of universal conductance fluctuations in three-dimensional topological semimetals|url=https://link.aps.org/doi/10.1103/PhysRevB.96.134201|journal=Physical Review B|volume=96|issue=13|pages=134201|doi=10.1103/PhysRevB.96.134201|arxiv=1708.05212|bibcode=2017PhRvB..96m4201H|s2cid=119451098 }}