Origins of Electromagnetic Radiation from Spintronic Terahertz Emitters: A Time-Dependent Density Functional Theory plus Jefimenko Equations Approach.

Microscopic origins of charge currents and electromagnetic (EM) radiation generated by them in spintronic THz emitters-such as, femtosecond laser pulse-driven single magnetic layer or its heterostructures with a nonmagnetic layer hosting strong spin-orbit coupling (SOC)-remain poorly understood despite nearly three decades since the discovery of ultrafast demagnetization. We introduce a first-principles method to compute these quantities, where the dynamics of charge and current densities is obtained from real-time time-dependent density functional theory, which are then fed into the Jefimenko equations for properly retarded electric and magnetic field solutions of the Maxwell equations. By Fourier transforming different time-dependent terms in the Jefimenko equations, we unravel that in the 0.

Tunable interlayer excitons and switchable interlayer trions via dynamic near-field cavity.

Emerging photo-induced excitonic processes in transition metal dichalcogenide (TMD) heterobilayers, e.g., interplay of intra- and inter-layer excitons and conversion of excitons to trions, allow new opportunities for ultrathin hybrid photonic devices.

Dielectric Engineering Boosts the Efficiency of Carbon Nanotube Photodiodes.

Carbon nanotube (CNT) photodiodes are a promising system for high-efficiency photocurrent generation due to the strong Coulomb interactions that can drive carrier multiplication. If the Coulomb interactions are too strong, however, exciton formation can hamper photocurrent generation. Here, we explore, experimentally and theoretically, the effect of the environmental dielectric constant (ε) on the photocurrent generation process in CNTs.