Optimally doped silver selenide and silver telluride exhibit linear positive magnetoresistance over decades in magnetic field and on a scale comparable to the colossal magnetoresistance compounds. We use hydrostatic pressure to smoothly alter the band structure of Ag-rich and Ag-deficient samples of semiconducting ${\mathrm{Ag}}_{2\pm \delta }\mathrm{Te}$ of fixed stoichiometry and disorder. We find that the magnetoresistance spikes and the linear field dependence emerges when the bands cross and the Hall coefficient changes sign.

• Received 25 June 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.066602