JOURNAL OF APPLIED PHYSICS, v.120, no.8, pp.084303
Publisher
AMER INST PHYSICS
Abstract
Using wave function matching approach and employing the Landauer-Buttiker formula, a ferromagnetic
graphene junction with temperature gradient across the system is studied. We calculate the
thermally induced charge and spin current as well as the thermoelectric voltage (Seebeck effect) in
the linear and nonlinear regimes. Our calculation revealed that due to the electron-hole symmetry,
the charge Seebeck coefficient is, for an undoped magnetic graphene, an odd function of chemical
potential while the spin Seebeck coefficient is an even function regardless of the temperature gradient
and junction length. We have also found with an accurate tuning external parameter, namely, the
exchange filed and gate voltage, the temperature gradient across the junction drives a pure spin current
without accompanying the charge current. Another important characteristic of thermoelectric
transport, thermally induced current in the nonlinear regime, is examined. It would be our main finding
that with increasing thermal gradient applied to the junction the spin and charge thermovoltages
decrease and even become zero for non zero temperature bias. Published by AIP Publishing.