Longitudinal Magnetoresistance and ''Chiral'' Coupling in Silver Chalcogenides

A complex longitudinal magnetoresistance (MR//) effect in the non-stoichiometric silver chalcogenides (include the silver selenide and telluride) has been found, however the mechanism for the MR// effect is not clear now. In this work, a new random resistor network for MR// effect is proposed based on the experimental observation. The network is constructed from six-terminal resistor units and the mobility of carries within the network has a Gaussian distribution. Considering the non-zero transverse-longitudinal coupling in materials, the resistance matrix of the six-terminal resistor unit is modified. It is found that the material has the ''chiral'' transverse-longitudinal couplings, which is suggested a main reason for the complex MR// effect. The model predictions are compared with the experimental results. A three dimension (3D) visualization of current flow within the network demonstrates the ''current jets'' phenomenon in the thickness of materials clearly. (condensed matter: electronic structure, electrical, magnetic, and optical properties)