T-linear resistivity from magneto-elastic scattering: Application to PdCrO₂

An electronic solid with itinerant carriers and localized magnetic moments represents a paradigmatic strongly correlated system. The electrical transport properties associated with the itinerant carriers, as they scatter off these local moments, have been scrutinized across a number of materials. Here, we analyze the transport characteristics associated with ultraclean PdCrO₂—a quasi-two-dimensional material consisting of alternating layers of itinerant Pd-electrons and Mott-insulating CrO₂ layers—which shows a pronounced regime of T-linear resistivity over a wide range of intermediate temperatures. By contrasting these observations to the transport properties in a closely related material PdCoO₂, where the CoO₂ layers are band-insulators, we can rule out the traditional electron–phonon interactions as being responsible for this interesting regime. We propose a previously ignored electron-magneto-elastic interaction between the Pd-electrons, the Cr local moments and an out-of-plane phonon as the main scattering mechanism that leads to the significant enhancement of resistivity and a T-linear regime in PdCrO₂ at temperatures far in excess of the magnetic ordering temperature. We suggest a number of future experiments to confirm this picture in PdCrO₂ as well as other layered metallic/Mott-insulating materials.