Electrical and Thermal Bias‐Driven Negative Magnetoresistance Effect in an Interacting Quantum Dot

Abstract

Spin‐dependent electron transport is theoretically studied for a system with an interacting quantum dot sandwiched between a pair of ferromagnetic electrodes. By separately applying an electrical bias or a temperature gradient across the junction, a spin‐polarized current can be obtained and controlled by tuning the gate voltage. Interestingly, regardless of whether the electron transport is driven by the bias voltage or temperature difference, the current in the device always exhibits negative magnetoresistance under the control of the gate voltage. Such magnetoresistance anomalies in the current profile originate from the spin‐selective tunneling channels in quantum dots, which have been proven experimentally feasible. This device scheme is compatible with current technologies and has potential applications in spintronics or spin caloritronics.