Spin and charge Nernst effect in a four-terminal double-dot interferometer

We investigate the spin and charge Nernst effect of a four-terminal Aharonov-Bohm interferometer with Rashba spin-orbit interaction (RSOI). It is shown that a pure spin Nernst effect or a fully spin-polarized Nernst effect can be obtained by modulating the magnetic flux phase ϕ and the RSOI induced phase φ. It is also demonstrated that some windows of ϕ (or φ) for maintaining an almost fully spin-polarized Nernst effect exist and their width is under the control of the other phase. Moreover, for the charge Nernst coefficient Nc and spin Nernst coefficient Ns the relationship Nc(ϕ,φ)=−Ns(φ,ϕ) always holds. These results suggest that our proposal may act as a controllable thermospin generator.