  The technique of conventional ferromagnet/heavy-metal spin-orbit torque (SOT)
offers significant potential for enhancing the efficiency of magnetic memories.
However, it faces fundamental physical limitations, including hunting effects
from the metallic layer, broken symmetry for enabling antidamping switching,
spin scattering caused by interfacial defects, and sensitivity to stray
magnetic fields. To address these issues, we here propose a van der Waals (vdW)
field-free SOT antiferromagnetic memory using a vdW bilayer LaBr$_2$ (an
antiferromagnet with perpendicular magnetic anisotropy) and a monolayer T$_d$
phase WTe$_2$ (a Weyl semimetal with broken inversion symmetry). By
systematically employing density functional theory in conjunction with
non-equilibrium Green's function methods and macrospin simulations, we
demonstrate that the proposed vdW SOT devices exhibit remarkably low critical
current density approximately 10 MA/cm$^2$ and rapid field-free magnetization
switching in 250 ps. This facilitates excellent write performance with
extremely low energy consumption. Furthermore, the device shows a significantly
low read error rate, as evidenced by a high tunnel magnetoresistance ratio of
up to 4250%. The superior write and read performance originates from the unique
strong on-site (insulating phase) and off-site (magnetic phase) Coulomb
interactions in electride LaBr$_2$, a large non-zero z-component polarization
in WTe$_2$, and the proximity effect between them.
