Antisymmetric Magnetoresistance in a CrTe₂/Bi₂Te₃/CrTe₂ van der Waals Heterostructure Grown by MBE

Abstract

The magnetoresistance (MR) of spin valves usually displays a symmetric dependence on the magnetic field. An antisymmetric MR phenomenon has been discovered recently that breaks field symmetry and has the potential to realize polymorphic memory. In this work, centimeter-size and high-quality CrTe₂/Bi₂Te₃/CrTe₂ van der Waals (vdWs) heterostructure devices have been prepared using molecular beam epitaxy (MBE). By changing the magnetization direction of the top and bottom layers of CrTe₂, an antisymmetric MR effect with high, intermediate, and low resistance states has been found and persists up to 75K. The emergence of this antisymmetric MR phenomenon is attributed to the spin Hall effect, which generates spin currents with both spin-up and spin-down orientations on the upper and lower surfaces of Bi₂Te₃. The spin currents diffuse or reflect at the Bi₂Te₃/CrTe₂ interfaces alongside the additional charge currents induced by the inverse spin Hall effect (ISHE). Through theoretical calculations, the existence of the antisymmetric MR effect has also been confirmed. Our work emphasizes the use of the MBE technology to grow vdWs heterostructures to explore new physical phenomena and potential applications of spin electronic devices in polymorphic solid-state storage.