The quenched domain mode of the photo-activated charge domain （PACD） in semi-insulating （SI） GaAs photoconductive semiconductor switches （PCSSs） is observed. We find that the quenched domain is induced by the in...The quenched domain mode of the photo-activated charge domain （PACD） in semi-insulating （SI） GaAs photoconductive semiconductor switches （PCSSs） is observed. We find that the quenched domain is induced by the instantaneous electric field across the PCSS being lower than the sustaining electric field of the domain during the transit of the domain. The extinction of the domain before reaching the anode can lead to a current oscillation frequency larger than the transit- time frequency when the bias electric field is lower than the threshold electric field of the nonlinear PCSS. According to the operation circuit and the physical properties of a high-field domain,an equivalent circuit of the quenched domain is presented. The equivalent circuit parameters including capacitance, resonant frequency, and inductance are calculated and measured. Our calculations agree well with the experimental results. This research provides theoretical and experimental criteria for heightening the oscillation frequency and efficiency of PACD devices.展开更多
Based on the tight-binding calculations on honeycomb lattice and photonic experimental visualization on artificial graphene(AG), we report the domain-wall-induced gapped topological kink states and topological corner ...Based on the tight-binding calculations on honeycomb lattice and photonic experimental visualization on artificial graphene(AG), we report the domain-wall-induced gapped topological kink states and topological corner states. In honeycomb lattice, domain walls(DWs) with gapless topological kink states could be induced either by sublattice symmetry breaking or by lattice deformation. We find that the coexistence of these two mechanisms will induce DWs with gapped topological kink states. Significantly, the intersection of these two types of DWs gives rise to topological corner state localized at the crossing point.Through the manipulation of the DWs, we show AG with honeycomb lattice structure not only a versatile platform supporting multiple topological corner modes in a controlled manner, but also possessing promising applications such as fabricating topological quantum dots composed of gapped topological kink states and topological corner states.展开更多
文摘The quenched domain mode of the photo-activated charge domain （PACD） in semi-insulating （SI） GaAs photoconductive semiconductor switches （PCSSs） is observed. We find that the quenched domain is induced by the instantaneous electric field across the PCSS being lower than the sustaining electric field of the domain during the transit of the domain. The extinction of the domain before reaching the anode can lead to a current oscillation frequency larger than the transit- time frequency when the bias electric field is lower than the threshold electric field of the nonlinear PCSS. According to the operation circuit and the physical properties of a high-field domain,an equivalent circuit of the quenched domain is presented. The equivalent circuit parameters including capacitance, resonant frequency, and inductance are calculated and measured. Our calculations agree well with the experimental results. This research provides theoretical and experimental criteria for heightening the oscillation frequency and efficiency of PACD devices.
基金This work was supported by the National Basic Research Program of China(2019YFA0308403)the National Natural Science Foundation of China(11534001,11822407 and 11874274)+2 种基金Natural Science Foundation of Jiangsu Province(BK20170058)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)We are grateful to H.M.Weng and H.W.Liu for helpful discussion.
文摘Based on the tight-binding calculations on honeycomb lattice and photonic experimental visualization on artificial graphene(AG), we report the domain-wall-induced gapped topological kink states and topological corner states. In honeycomb lattice, domain walls(DWs) with gapless topological kink states could be induced either by sublattice symmetry breaking or by lattice deformation. We find that the coexistence of these two mechanisms will induce DWs with gapped topological kink states. Significantly, the intersection of these two types of DWs gives rise to topological corner state localized at the crossing point.Through the manipulation of the DWs, we show AG with honeycomb lattice structure not only a versatile platform supporting multiple topological corner modes in a controlled manner, but also possessing promising applications such as fabricating topological quantum dots composed of gapped topological kink states and topological corner states.
