Low power In Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures

Abstract

The surface state of a 3D topological insulator (3DTI) is a spin-momentum locked conductive state, whose large spin hall angle can be used for the energy-efficient spin orbit torque based switching of an overlying ferromagnet (FM). Conversely, the gated switching of the magnetization of a separate FM in or out of the TI surface plane, can turn on and off the TI surface current. The gate tunability of the TI Dirac cone gap helps reduce its sub-threshold swing. By exploiting this reciprocal behaviour, we can use two FM/3DTI heterostructures to design a 1-Transistor 1-magnetic tunnel junction random access memory unit (1T1MTJ RAM) for an ultra low power Processing-in-Memory (PiM) architecture. Our calculation involves combining the Fokker-Planck equation with the Non-equilibrium Green Function (NEGF) based flow of conduction electrons and Landau-Lifshitz-Gilbert (LLG) based dynamics of magnetization. Our combined approach allows us to connect device performance metrics with underlying material parameters, which can guide proposed experimental and fabrication efforts.

5 pages, 4 figures

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• Large-gap magnetic topological heterostructure formed by subsurface incorporation of a ferromagnetic layer
• Field-free switching of magnetic tunnel junctions driven by spin-orbit torques at sub-ns timescales
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• Low power In Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures
• Proximity induced ferromagnetism, superconductivity, and finite-size effects on the surface and edge states of topological insulator nanostructures

Cited by in corpus (3)

• Low power In Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures
• Strained topological insulator spin-orbit torque random access memory (STI-SOTRAM) bit cell for energy-efficient Processing in Memory
• Enhanced detection of circularly polarized photons with topological materials