Y.V. Turkin – Senior Research Scientist,
NIKA-Microwave, Ltd (Saratov)
E-mail: turkin.yaroslav@gmail.com
A.S. Gubina – student,
Yuri Gagarin State Technical University of Saratov
E-mail: anna.gubina1@icloud.com
In this work, we theoretically investigate photoexcitation of the nonequillibrium spin accumulation in two-dimensional Dirac material with spin-orbit coupling. Direction of the nonequillibrium spin-accumulation calculated from the numerical solutions of the density matrix equations of motion. In the sake of simplicity, we take into account only direct optical transitions between conductance and valence bands with the different values of spin. Interaction of the electrons with the defects of lattice and their recombination taken into account through the relaxation time approximation. Eigenfunctions and eigenenergies of pristine Dirac material calculated analytically and exchange interaction of conduction-band electrons with the lattice magnetization treated numerically with the first order of perturbation theory. Spin accumulation calculated from the numerical solutions of the density matrix equations of motion with the help of block-diagonal spin operators. We show that formation of the spin accumulation under circular-polarized light illumination creates a spin transfer torque. This optically induced spin transfer torque acts on surface magnetization of substrate. This effect has potential applications for the spin-wave generation in thin ferromagnetic and antiferromagnetic films.
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