Current Jets, Disorder, and Linear Magnetoresistance in the Silver Chalcogenides

Abstract

The inhomogeneous distribution of excess or deficient silver atoms lies behind the large and linear transverse magnetoresistance displayed by ${\mathrm{Ag}}_{2\ifmmode\pm\else\textpm\fi{}\ensuremath{\delta}}\mathrm{Se}$ and ${\mathrm{Ag}}_{2\ifmmode\pm\else\textpm\fi{}\ensuremath{\delta}}\mathrm{Te}$, introducing spatial conductivity fluctuations with length scales independent of the cyclotron radius. We report a negative, nonsaturating longitudinal magnetoresistance up to at least 60 T, which becomes most negative where the bands cross and the effect of conductivity fluctuations is most acute. Thinning samples down to $10\text{ }\ensuremath{\mu}\mathrm{m}$ suppresses the negative response, revealing the essential length scale in the problem and paving the way for designer magnetoresistive devices.