Unidirectional Magnetoresistance in Antiferromagnet/Heavy-Metal Bilayers

Coexistence of Magnon-Induced and Rashba-Induced Unidirectional Magnetoresistance in Antiferromagnets

“…Note that magnon is the dominant origin but not the sole origin of UMR at 2 T since UMR at 2 T still exists at 100 K as shown in Figure (b). This residual part of UMR should have the same origin as UMR at 8 T. For this type of UMR, we attribute it to the interfacial Rashba splitting theory that has been introduced in the FeRh/Pt system . To confirm the existence of Rashba splitting at the YFO/Pt interface, we perform density functional theory calculations (see details in Supporting Information S5).…”

“…The observed FM UMR can mainly be attributed to two origins, i.e., spin-dependent electron scattering and spin-flip electron–magnon scattering. − UMR is initially not expected in AFM materials where the spin polarizations of two magnetic sublattices cancel each other out. Until recently, scientists proposed that AFM UMR can be induced by Rashba splitting and Néel vector canting in metallic AFM systems under a large external magnetic field . Besides, some works suggest that magnon can also induce UMR in AFM systems. − However, a complete understanding of AFM UMR’s origin, as an analogue to FM UMR theory, is still lacking.…”

“…Until recently, scientists proposed that AFM UMR can be induced by Rashba splitting and Neél vector canting in metallic AFM systems under a large external magnetic field. 26 Besides, some works suggest that magnon can also induce UMR in AFM systems. 27−29 However, a complete understanding of AFM UMR's origin, as an analogue to FM UMR theory, is still lacking.…”

“…This residual part of UMR should have the same origin as UMR at 8 T. For this type of UMR, we attribute it to the interfacial Rashba splitting theory that has been introduced in the FeRh/Pt system. 26 To confirm the existence of Rashba splitting at the YFO/Pt interface, we perform density functional theory calculations (see details in Supporting Information S5). The calculated electronic band structure clearly shows a large Rashba splitting in the energy range of ∼0.05−0.1 eV at the YFO/Pt interface as shown in Figure 4(b) and Figure S4.…”

“…As a comparison, the reported Rashba-induced UMR in the Pt/FeRh system experiences a characteristic sign change. 26 The tendency difference is understandable since Rashba-induced UMR should be sensitive to the interfacial band structure. Given different material systems, the distortion speed of the Fermi contours varies distinctly.…”