Band tilt induced nonlinear Nernst effect in topological insulators: An efficient generation of high-performance spin polarization

Topological insulators (TIs) hold promise as a platform for spintronics applications due to the fascinating spin-momentum locking (SML) of surface states. One particular interest lies in using TIs spin-polarized sources structures. Here, we propose band tilt induced nonlinear Nernst effect (NLNE) clean and efficient route generate high-performance spin polarization (SP). We show that presence SML hexagonal warping finite can induce an imbalance two carriers effectively give rise NLNE current TIs. In our scheme, both charge regime be achieved under thermal drive. The obtainable SP efficiently tuned either smooth or rapid way, exhibiting highly flexible tunability. addition, near-unity generated within wide range tunable parameters, which is also found robust against temperature. Therefore, work provides mechanism realize controllable room-temperature high-degree based on TIs, essential importance future applications.