5 papers
Ab initio time-dependent GW approach for nonequilibrium exciton-phonon coupled dynamics across momentum space
Zhenfa Zheng, Benran Zhang, Jiawei Ruan +10
The dynamics of optical excitations in materials generally involves intertwined electron-hole (e-h) and electron-phonon (e-ph) interactions out of equilibrium. However, a full theo…
Quantum Theory of Exciton Magnetic Moment: Interaction and Topological Effects
Gurjyot Sethi, Jiawei Ruan, Fang Zhang +4
Combining magnetometry with optical spectroscopy has uncovered novel quantum phenomena and is emerging as a powerful probe of quantum materials. However, the theory of the magnetic…
Destructive interference of second harmonic generation in AA stacked MoTe/WSe
Yiduo Wang, Yao Lu, Changshen Chen +14
The stacking configuration of two-dimensional materials critically governs their optical and electronic responses. Monolayer transition-metal dichalcogenides (TMDC) lack inversion…
Exciton enhanced nonlinear optical responses in monolayer h-BN and MoS2: Insight from first-principles exciton-state coupling formalism and calculations
Jiawei Ruan, Y. -H. Chan, Steven G. Louie
Excitons are vital in the photophysics of materials, especially in low-dimensional systems. The conceptual and quantitative understanding of excitonic effects in nonlinear optical…
Ab initio study of exciton insulator phase: Emergent -wave spin textures from spontaneous excitonic condensation
Fang Zhang, Jiawei Ruan, Gurjyot Sethi +2
An excitonic insulator (EI) is a correlated many-body state of electron-hole pairs, potentially leading to high-temperature condensate and superfluidity. Despite ev…