Continuous Chirality Measure on Spin and Orbital Polarization, and Optical Activity in Solids

Chirality introduces intriguing topological, electronic, and optical properties to molecules and
solids. In this work, we investigate the influence of structural chirality on spin and orbital po-
larization as well as optical activity through first-principles calculations and continuous chirality
measures (CCM). By using chiral selenium (Se) and 2D hybrid perovskites as examples, we demon-
strate that chirality continuously modify spin-orbit splitting and orbital angular momentum (OAM)
polarization. We establish a direct connection between chirality transfer across organic-inorganic
interfaces and inversion symmetry breaking, which induces Rashba-Dresselhaus spin splitting in hy-
brid perovskites. Additionally, we examine the effects of chirality on circular dichroism (CD) and the
circular photogalvanic effect (CPGE), demonstrating how the continuous chirality measures dictate
their magnitude and anisotropy.
Next, we will discuss our recently developed computational framework that combines first-principles density-matrix dynamics including quantum scatterings such as electron-phonon coupling with self-consistent spin-orbit coupling, with the Wigner function formalism for spatial resolution. With such methods, we show examples of studying spin relaxation and chiral-induced spin selectivity (CISS) in chiral materials. Our studies reveal the mechanism and offer design principles for materials with optimal CISS and novel spintronic devices with efficient spin and orbital manipulation.

*This project is funded by DOE Computational Chemical Science under grant number DE-SC0023301
and EFRC-CHOISE center.