Giant Anisotropic Magnetoresistance in Magnetic Monolayers CrPX3 (X = S, Se, Te) due to symmetry breaking between the in-plane and out-of-plane crystallographic axes

Abstract: Anisotropic magnetoresistance (AMR) has a crucial feature for developing highly sensitive sensors and innovative memory devices. While extensively studied in bulk materials, AMR effects in these materials are typically weak. Recent advancements indicate that two-dimensional (2D) van der Waals magnetic materials possess unique magnetic properties, potentially including significant AMR characteristics. In this study, we utilize density functional theory and the Boltzmann transport equation to investigate AMR in magnetic monolayers CrPX3 (X = S, Se, Te). Our findings reveal a substantially large AMR in these 2D magnetic compounds. This enhancement is attributed to magnetization (M)-dependent spin-orbit coupling (SOC), arising from the broken symmetry between in-plane and out-of-plane orientations. This results in significant M-dependent band splitting and subsequent variations in electron velocity. Additionally, we find that the M-dependent SOC is significantly enhanced by increasing the atomic number of the chalcogen X in CrPX3, achieving an exceptional 150% AMR in CrPTe3. Furthermore, our study demonstrates that AMR can be effectively modulated by applying biaxial strain, resulting in a twofold increase with a 4% strain. These findings propose a novel approach to enhancing 2D-based AMR spintronic devices, making a substantial contribution to the field.