Ricardo Zarzuela
Johannes Gutenberg Universität, Mainz
The slave-boson approach [1], which is built upon the idea that hopping of electrons in the lattice is accompanied by a backflow of spin excitations, has played a significant role in the field of strongly correlated systems to describe metal-insulator transitions [2] and high-Tc superconductivity [3]. This formalism turns out to also be well suited for exploring transport phenomena in spintronics, since the spin exchange with the magnetic background can be easily incorporated into the associated representation of electron operators. We show that the slave-boson approach to the Hubbard model for conduction electrons (near half filling) yields an effective low-energy long-wavelength theory for the itinerant transport in metallic frustrated magnets [4]. In particular, in these frustrated platforms where the average macroscopic magnetization is zero, this formalism yields an emergent coupling between the itinerant spin current and the magnetization current that is responsible for the spin-transfer physics as well as the topological Hall effect in these platforms. We also show that topological defects (e.g., magnetic disclinations) mediate both spin-transfer and topological Hall responses in the magnetic medium [5], which have not been previously explored experimentally.
References
[1] P. Coleman, Phys. Rev. B 29, 3035 (1984).
[2] G. Kotliar and A.E. Ruckenstein, Phys. Rev. Lett. 57, 1362 (1986); P. Entel et al., Int. J. Mod. Phys. B 5, 271 (1991). [3] G. Kotliar and J. Liu, Phys. Rev. B 38, 5142 (1988); P.A. Lee and N. Nagaosa, Phys. Rev. B 46, 5621 (1992). [4] R. Zarzuela and J. Sinova, Phys. Rev. B 105, 024423 (2022). [5] R. Zarzuela and J. Sinova, arXiv:2112.06680 (2022).