Spin-thermoelectric transport induced by interactions and spin-flip   processes in two dimensional topological insulators
  We consider thermoelectric transport properties of the edge states of a two dimensional topological insulator in a double quantum point contact geometry coupled to two thermally biased reservoirs. Both spin-preserving and spin-flipping tunneling processes between opposite edges are analyzed in the presence of electron-electron interactions. We demonstrate that the simultaneous presence of spin-flipping processes and interactions gives rise to a finite longitudinal spin current. Moreover, its sign and amplitude can be tuned by means of gate voltages with the possibility to generate a pure spin current, with a vanishing charge current. 
Flavio Ronetti, Luca Vannucci, Giacomo Dolcetto, Matteo Carrega, Maura   Sassetti
cond-mat.mes-hall