2007/05/03 by Jingshi Hu, Meera M. Parish, T. F. Rosenbaum · 4 citations
Mathematics · Physics and Astronomy · #Condensed matter physics #Diagonal #Electrical conductor #Electrical resistivity and conductivity #Geometry #Magnetic field #Magnetic properties of thin films #Magnetoresistance #Mathematics #Physics #Quantum and electron transport phenomena #Quantum mechanics #Tensor (intrinsic definition) #Theoretical and Computational Physics #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.75.214203
published as Phys. Rev. B 75, 214203 (2007) · 10 pages, 7 figures
arxiv created 2007/05/03 · openalex publication_date 2007/06/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The silver chalcogenides provide a striking example of the benefits of imperfection. Nanothreads of excess silver cause distortions in the current flow that yield a linear and nonsaturating transverse magnetoresistance (MR). Associated with the large and positive MR is a negative longitudinal MR. The longitudinal MR only occurs in the three-dimensional limit and thereby permits the determination of a characteristic length scale set by the spatial inhomogeneity. We find that this fundamental inhomogeneity length can be as large as 10\phantom\rule0.3em0ex\ensuremathμm. Systematic measurements of the diagonal and off-diagonal components of the resistivity tensor in various sample geometries show clear evidence of the distorted current paths posited in theoretical simulations. We use a random-resistor network model to fit the linear MR, and expand it from two to three dimensions to depict current distortions in the third (thickness) dimension. When compared directly to experiments on Ag_2\ifmmode±\else\textpm\fi\ensuremathδSe and Ag_2\ifmmode±\else\textpm\fi\ensuremathδTe, in magnetic fields up to 55\phantom\rule0.3em0exT, the model identifies conductivity fluctuations due to macroscopic inhomogeneities as the underlying physical mechanism. It also accounts reasonably quantitatively for the various components of the resistivity tensor observed in the experiments.