Time-dependent approach on the spin-charge separation in chiral geometric material

Spin-charge separation is a phenomenon observed in strongly correlated materials, where the spin and charge of an electron behave independently, resulting in distinct excitations. Unlike in traditional electron systems where spin and charge are bound, one-dimensional systems like Tomonaga-Luttinger liquids allow for their decoupling, enabling the charge (holon) and spin (spinon) to propagate separately at different velocities. Experimental measurements and theoretical calculations on spin dynamics in chiral crystals, particularly natural crystals such as chiral Te and Se, have also been widely explored across various aspects.

In this work, we aim to investigate spin-charge separation in one-dimensional chiral chains using real-time time-dependent density functional theory (rt-TDDFT). Historically, studies of spin-charge separation have relied on many-body models, with limited research conducted using density functional theory (DFT). DFT indirectly considers many-body interactions through the Hartree potential (electrostatic interaction) and exchange-correlation potential (quantum mechanical interaction), reducing computational complexity while providing an effective electronic structure. To address its limitations, we also use DFT+U corrections to improve the accuracy of many-body interactions.

Real-time studies of spin and charge dynamics in chiral chains are particularly rare. Given the unique spin dynamics characteristic of chiral chains, we aim to analyze the spin and charge dynamics in chiral 1D wires from the perspective of spin-charge separation. Additionally, we investigate the conditions under which spin-charge separation occurs, focusing on the presence or absence of chirality, SOC, and many-body interactions. By incorporating DFT+U, we address incomplete treatments of many-body interactions and provide a comprehensive analysis of spin-charge separation in chiral systems.