Canted magnetism and topological spin texture induced in silicon from flexoelectronic proximity effect

Abstract

The flexoelectronic effect leads to charge carrier transfer between two dissimilar materials, a combination of metal and doped semiconductor, when they are brought into contact under an applied strain gradient. The flexoelectronic effect may lead to continuity of electronic wavefunction and order parameter across the interface, which is called as flexoelectronic proximity effect. This study experimentally demonstrates flexoelectronic proximity effect induced canted magnetic moment in the doped p-Si thin film from ferromagnetic permalloy thin film, which give rise to RKKY interlayer exchange interaction between permalloy and p-Si layers. The canted magnetic moment manifests topological spin-Seebeck effect response in magneto-thermoelectric measurements. The topological spin-Seebeck effect is likely to arise due to inverse spin-Hall effect from topological spin texture; possibly a three-dimensional analogue of the hexagonally warped helical spin texture. This work demonstrates that thermal modulation of strain gradient can be used to tune RKKY interlayer exchange interaction between Py and p-Si from ferromagnetic to antiferromagnetic as well as magnitude of the canted magnetic moment. The canted magnetic moment and topological spin texture behavior can also be controlled by varying the thickness of the p-Si layer. The flexoelectronic proximity effect and topological spin texture can enable Si based spin, magnetic, topological and quantum applications.