Topological-insulator-based non-volatile memory cells: A quantum device simulation

We developed a quantum transport model to simulate the spin-resolved transport properties of a topological insulator (TI) spintronic memory device, which can capture the spin-momentum locking of surface states in TIs and deal with Klein tunneling and coupled spin dynamics. We present a simple design of spin-transfer torque (STT) device which consists of a thin layer TI coupled with a top ferromagnetic film. The device removes the requirement of spin-polarized contacts and magnetic tunnel junctions (MTJs) in conventional STT memory cells by exploiting spin-momentum locking of the TI surface states. The analysis shows that by introducing partial perpendicular magnetic anisotropy (PPMA), both fast switching and low switching current can be achieved.