Spin Relaxation and Optronics Properties of Solids from Ab-initio Density-Matrix Dynamics

Ab initio spin dynamics and transport simulations are critical for predicting new materials and realizing the potential of spintronics, spin-based quantum information science, and spin-selective photo-chemistry. In particular, simulations would be invaluable to predict key physical parameters including spin lifetime, spin diffusion and coherence length, magneto-optical spectra, and (spin)-photocurrent.



In this presentation we will introduce our recently developed real-time density-matrix dynamics approach based on Lindbladian dynamics with first-principles electron-electron, electron-phonon, electron-impurity scatterings and self-consistent spin-orbit coupling[1-3]. We are developing a computational framework and an open-source implementation for simulating spatio-temporal quantum dynamics and transport accounting for a range of quantum degrees of freedom (e.g., charge, spin, orbital, lattice).



We show our methods can accurately predict spin and carrier lifetime, spin diffusion length, and pump-probe Kerr-rotation signatures for general solids, with examples of Si, GaAs, 2D materials[4], and hybrid halide perovskites[5-6]. In particular, we show our recent study of how g factor fluctuations (including orbital angular momentum) lead to spin dephasing in halide perovskites under external magnetic field, and we will show the distinct electron-phonon contributions to spin and carrier relaxations and crucial dependence on crystal symmetry[6].

We next will introduce our recent progress of developing methodology for spin-optotronic signatures, such as circular dichroism and circular/spin photogalvanic effect to chiral and broken-inversion-symmetry solid[7,8]. Importantly, with our real-time density matrix dynamics, we can describe full quantum kinetics process of excitation, scattering, and recombination from first-principles. Such formalism can also be applied to computing various transient and steady-state photocurrents or nonlinear optics. Finally, we will present initial results on first-principles prediction of spatial-temporal spin transport properties in graphene and chiral materials. Our results provide important insights for spin-optotronic properties and spin and orbital transport in chiral and non-centrosymmetric systems.