We study the photoluminescence dynamics of ultracold indirect excitons optically created in a double-quantum-well heterostructure in the regime in which the inner photoluminescence ring is formed. We show that the spectrally resolved dynamics is in agreement with an excitonic origin for the inner ring which appears due to the local heating of indirect excitons by laser excitation. To confirm this interpretation and exclude the ionization of indirect excitons, we evaluate the excitonic density that is extracted from the energy of the photoluminescence emission. It is shown that optically injected carriers play a crucial role in that context as these are trapped in our field-effect device and then vary the electrostatic potential controlling the confinement of indirect excitons. This disruptive effect blurs the estimation of the exciton concentration. However, it is suppressed by placing the double quantum well behind a superlattice where a fraction of photoinjected carriers remains trapped and then screens fluctuations of the electrostatic potential at the gate electrodes. In this improved geometry, we then estimate that the exciton density remains one order of magnitude smaller than the critical density for the ionization of indirect excitons (or Mott transition) in the regime where the inner ring is formed.
机构:
Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USAUniv Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA
Butov, LV
Gossard, AC
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机构:Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA
Gossard, AC
Chemla, DS
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机构:Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA
机构:
Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USAUniv Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA
Butov, LV
Gossard, AC
论文数: 0引用数: 0
h-index: 0
机构:Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA
Gossard, AC
Chemla, DS
论文数: 0引用数: 0
h-index: 0
机构:Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA