Sayed, Shehrin Hong, Seokmin Datta, Supriyo 2024-01-19T21:30:43Z 2024-01-19T21:30:43Z 2021-09-05 2018-11-20 2331-7019 https://pubs.kist.re.kr/handle/201004/120670 We provide a transmission-line representation for channels exhibiting spin-momentum locking (SML) that can be used for both time-dependent and steady-state transport analysis on a wide variety of materials with spin-orbit coupling such as topological insulators, Kondo insulators, transition metals, semimetals, oxide interfaces, and narrow band-gap semiconductors. This model is based on a time-dependent four-component diffusion equation obtained from the Boltzmann transport equation assuming linear response and elastic scattering in the channel. We classify all electronic states in the channel into four groups (U+, D+, U-, and D-) depending on the spin index [up (U), down (D)] and the sign of the x component of the group velocity (+,-) and assign an average electrochemical potential to each of the four groups to obtain the four-component diffusion equation. For normal metal channels, the model decouples into the well-known transmission-line model for charge and a time-dependent version of the Valet-Fert equation for spin. We first show that, in the steady-state limit, our model leads to simple expressions for charge-spin interconversion in SML channels in good agreement with existing experimental data on diverse materials. We then use the full time-dependent model to study spin-charge separation in the presence of SML, a subject that has been controversial in the past. Our model shows that the charge and spin signals travel with two distinct velocities, resulting in well-known spin-charge separation, which is expected to persist even in the presence of SML. However, our model predicts that the lower velocity signal is purely spin, while the higher velocity signal is largely charge with an additional spin component proportional to the degree of SML, which has not been noted before. Finally, we note that our model can be used within standard circuit simulators such as SPICE to obtain numerical results for complex geometries. English AMER PHYSICAL SOC ELECTRICAL DETECTION POLARIZED CURRENTS CIRCUIT MODEL CHANNELS STATES Transmission-Line Model for Materials with Spin-Momentum Locking Article 10.1103/PhysRevApplied.10.054044 1 PHYSICAL REVIEW APPLIED, v.10, no.5 PHYSICAL REVIEW APPLIED 10 5 scie scopus 000451012400001 2-s2.0-85057136084 Physics, Applied Physics Article ELECTRICAL DETECTION POLARIZED CURRENTS CIRCUIT MODEL CHANNELS STATES spin momentum locking transmission line model spin orbit coupling spin Hall effect Rashba topological insulator