11 research outputs found
Ring-shaped luminescence patterns in a locally photoexcited electron-hole bilayer
We report the results of molecular dynamics simulation of a spatiotemporal
evolution of the locally photoexcited electrons and holes localized in two
separate layers. It is shown that the ring-shaped spatial pattern of
luminescence forms due to the strong in-layer Coulomb interaction at high
photoexcitation power. In addition, the results predict (i) stationary spatial
oscillations of the electron density in quasi one-dimensional case and (ii)
dynamical phase transition in the expansion of two-dimensional electron cloud
when threshold electron concentration is reached. A possible reason of the
oscillations and a theoretical interpretation of the transition are suggested.Comment: 6 pages, 5 figures. Final version as published + Erratum has been
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Ring-shaped spatial pattern of exciton luminescence formed due to the hot carrier transport in a locally photoexcited electron-hole bilayer
A consistent explanation of the formation of a ring-shaped pattern of exciton
luminescence in GaAs/AlGaAs double quantum wells is suggested. The pattern
consists of two concentric rings around the laser excitation spot. It is shown
that the luminescence rings appear due to the in-layer transport of hot charge
carriers at high photoexcitation intensity. Interestingly, one of two causes of
this transport might involve self-organized criticality (SOC) that would be the
first case of the SOC observation in semiconductor physics. We test this cause
in a many-body numerical model by performing extensive molecular dynamics
simulations. The results show good agreement with experiments. Moreover, the
simulations have enabled us to identify the particular kinetic processes
underlying the formation of each of these two luminescence rings.Comment: 14 pages, 16 figures. Final versio