Thermospin diode effect based on a quantum dot system

• Model of thermal induced spin current diode made of FM leads and QD.
• Asymmetric character is essential for occurring current rectification.
• Coulomb charging energy plays indispensable role in rectification.
• High rectification of thermospin current is obtained with Zeeman magnetic field.

The rectification of spin current driven by a temperature difference in a simple model consisting of a quantum dot connected to two ferromagnetic leads has been studied using the rate equation technique. In addition to the dot level, the magnitude of thermospin current rectification depends on the temperature bias across the system, the asymmetry parameter and the Coulomb charging energy, where the last two parameters are necessary conditions for rectification to occur in the system. The thermospin current rectification becomes analytically simplified at the limitation condition of asymmetry. With an applied Zeeman magnetic field, an ideal 100%100% rectification of thermospin current can be obtained at specific dot energies, which can be controlled by an external gate voltage.