2024/12/02 by Fırat Yılmaz, Yılmaz, Fırat
Physics and Astronomy · Mathematics · #Quantum chaos and dynamical systems #Spectral Theory in Mathematical Physics #Quantum optics and atomic interactions
paper · pdf · doi:10.48550/arxiv.2412.01631
We propose a new route to generate an interband Dzyaloshinskii-Moriya interaction in metals from solely microscopic perspective. The system consists of conduction band electrons in the presence of the Rashba spin-orbit coupling which are coupled to a f(d)-type localized and interacting electrons. The double occupancy in the f-band is penalized by a significant Coulomb interaction energy, U. When the hybridization between two bands is not strictly local, it leads an alternative pathway to a spin Hamiltonian that may proliferate the formation of Skyrmion textures. The effective spin Hamiltonian is derived using the Schriffer-Wolff perturbation theory. In addition to a Kondo spin exchange interaction between conduction band spins and f(d)-band spins, which is denoted as sm ⋅ Sn, the spin Hamiltonian admits a \bf Dzyaloshinskii-Moriya spin coupling term, sm × Sn. The magnitude of the Dzyaloshinskii-Moriya term is approximately ten to hundred times smaller than that of the Kondo term under physically relevant assumptions. The magnitude of spin coupling terms can be engineered using time-dependent external fields, motivating a generalization to a effective time-dependent Hamiltonian. In this respect, the perturbative derivation is extended to include time-dependent external field using a time-dependent SW transformation. The form of the effective spin Hamiltonian is retained while the spin coupling coefficients gain time dependence. It has been shown that the DM term acquires a new energy scale, which leads to an enhancement of one to two orders of magnitude and makes it comparable to the Kondo coupling.