  The main contribution of this paper is to study the spin caloritronic effects
in defected graphene/silicene nanoribbon (GSNR) junctions. Each step-like GSNR
is subjected to the ferromagnetic exchange and local external electric fields,
and their responses are determined using the nonequilibrium Greens function
(NEGF) approach. To further study the thermoelectric (TE) properties of the
GSNRs, three defect arrangements of divacancies (DVs) are also considered for a
larger system, and their responses are re-evaluated. The results demonstrate
that the defected GSNRs with the DVs can provide an almost perfect thermal spin
filtering effect (SFE), and spin switching. A negative differential
thermoelectric resistance (NDTR) effect and high spin polarization efficiency
(SPE) larger than 99.99 percent are obtained. The system with the DV defects
can show a large spin-dependent Seebeck coefficient, equal to 1.2 mV/K, which
is relatively large and acceptable. Appropriate thermal and electronic
properties of the GSNRs can also be obtained by tuning up the DV orientation in
the device region. Accordingly, the step-like GSNRs can be employed to produce
high efficiency spin caloritronic devices with various features in practical
applications.
