Phys. Rev. B 60, 7944–7949 (1999)Action spectra of the two-stage photoinduced insulator-metal transition in Pr1-xCaxMnO3Received 6 November 1998; revised 1 April 1999; published in the issue dated 15 September 1999 The action spectra for the photoinduced insulator-metal transition in Pr1-xCaxMnO3 were investigated in the 0.45-3.05 eV range. The photon-density threshold for the transition exhibits a gaplike behavior at ∼0.4 eV with anisotropic features, and it is insensitive to the degree of carrier doping x. A two-stage mechanism is proposed for the transition. In the first stage, photoexcited charge carriers melt down the charge-ordered state by screening effects, which is followed by a local formation of metastable metallic domains. In the second stage, the barrier between the metallic domains is overcome by an applied electric field resulting in a continuous conducting path that remains stable as long as the current is maintained. © 1999 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.60.7944
DOI:
10.1103/PhysRevB.60.7944
PACS:
71.30.+h, 71.28.+d, 72.40.+w
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