Programme

P.63 -- Posters, VCTP-50

Date: Thursday, 7 August 2025

Time: 08:30 - 10:00

Optically controlled spin transport in topological insulator thin films

Tran Cong Phong (1,2), Le Thi Thu Phuong (3)

(1) Atomic Molecular and Optical Physics Research Group, Institute for Advanced Study in Technology, Ton Duc Thang University, Ho Chi Minh City; (2) Faculty of Electrical and Electronics Engineering, Ton Duc Thang University, Ho Chi Minh City; (3) Faculty of of Physics, University of Education, Hue University, Hue

We explore the spin Edelstein effect at low temperatures in topological insulator thin films irradiated with circularly polarized light. Employing a high-frequency Floquet framework, we derive an effective Hamiltonian that captures the light-induced modifications to the mass gap and Fermi velocity. Using this model, we calculate the spin Edelstein susceptibility via Kubo linear response theory, incorporating both intraband and interband contributions. Our results reveal that optical driving enables significant tunability of spin polarization, with critical behavior emerging near a Floquet-engineered topological phase transition, where the effective Fermi velocity approaches zero. We further show that surface asymmetry, hybridization strength, and interband relaxation processes critically influence the spin response. These findings highlight the potential for dynamic optical control of spin accumulation in topological materials, opening new avenues for spintronic device applications.

Presenter: Le Thi Thu Phuong