Tunable Spin Seebeck Diode with Magnonic Spin Tunneling Junction

We theoretically investigate the spin–wave spin current induced by the spin Seebeck effect in magnonic spin tunneling junctions (MSTJs) for arbitrary magnetization directions. We show that the MSTJ functions as a $\mathit{\text{tunable}}$ spin Seebeck diode in which the tunneling spin current can be turned on and off with high efficiency by controlling the magnetization direction.