Topological phonons in an inhomogeneously strained silicon4: Large spin dependent thermoelectric response and thermal spin transfer torque due to topological electronic magnetism of phonons
Abstract
The superposition of flexoelectronic doping and topological phonons give rise to topological electronic magnetism of phonon in an inhomogeneously strained Si in the bilayer structure with metal. In case of ferromagnetic metal and Si bilayer structure, the flexoelectronic doping will also give rise to larger spin current, which will lead to large spin to charge conversion due to topological electronic magnetism of phonon. By applying a temperature difference to ferromagnetic metal/Si bilayer structure under an applied strain gradient, a large thermoelectric response can be generated. In this experimental study, we report a large spin dependent thermoelectric response at Ni80Fe20/Si bilayer structure. The spin dependent response is found to be an order of magnitude larger than that in Pt thin films and similar to topological insulators surface states in spite of negligible intrinsic spinorbit coupling of Si. This large response is attributed to the flexoelectronic doping and topological electronic magnetism of phonons, which was uncovered using topological Nernst effect measurement. This alternative and novel approach of using inhomogeneous strain engineering to address both spin current density and spin to charge conversion can open a new window to the realization of spintronics and spincaloritronics devices using metal and dopedsemiconductor layered materials.
 Publication:

arXiv eprints
 Pub Date:
 October 2021
 arXiv:
 arXiv:2110.04939
 Bibcode:
 2021arXiv211004939B
 Keywords:

 Condensed Matter  Materials Science;
 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 Theoretical/modeling help welcome. Some devices can be shared for replication experiments