TEMT: A Transient Electronic–Magnetic–Thermal-Coupled Simulation Framework for STT-MTJs

Being a promising candidate for future nonvolatile memory and neuromorphic computing, spin-transfer-torque magnetic tunnel junction (STT-MTJ) devices are gaining substantial momentum in industrial adoption in recent years, calling for EDA support for higher modeling capabilities. However, the complex interplay of multiple physical mechanisms featured in MTJ devices imposes substantial challenges to their numerical modeling. In this work, we propose a fully coupled, transient electronic–magnetic–thermal (TEMT) modeling approach for STT-MTJ devices. Aiming to be the first principle and physically holistic, TEMT combines the atomistic nonequilibrium Green’s function (NEGF) model for tunneling currents, the Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation for magnetic dynamics and the heat conduction equation (HCE) for thermal dynamics in a self-consistent manner. To alleviate computational burden, we also devise an analytical approximation approach to reduce the number of NEGF solutions in the TEMT framework, which leads to over
$15\times $
speedup with a very mild accuracy loss. An in-depth investigation of STT-MTJ devices using the TEMT framework is conducted to demonstrate its benefits and performance.