An ideal candidate for observing anomalous Hall effect induced by the in-plane magnetic field

The anomalous Hall effect induced by the in-plane magnetic field (anomalous planar Hall effect) has recently attracted a lot of interests due to its numerous advantages. Although several schemes have been put forward in theory, experimental observations in many materials so far are often accompanied by planar Hall effects due to other mechanisms, rather than the pure anomalous planar Hall effect (APHE). We propose the surface state of the strained topological insulator as an ideal candidate to observe this effect. The surface state exhibits a pure APHE, characterized by a linear dependence on the magnetic field and a 2πperiodicity, which remains robust against the scattering of non-magnetic and various magnetic impurities, as long as the uniaxial strain preserves mirror symmetry. Although a general strain that breaks the mirror symmetry can induce the conventional Drude Hall effect, the anomalous contribution remains dominant. Furthermore, we present a feasible scheme to distinguish between the two contributions based on their distinct magnetic field dependencies. Our work is of great significance for promoting experimental observation of the APHE and provides reference value in the search for other realistic materials.