Action Spectra of the Two-Stage Photoinduced Insulator-Metal Transition in Pr1-xCaxMnO3
Action Spectra of the Two-Stage Photoinduced Insulator-Metal Transition in Pr1-xCaxMnO3
复制标题
Pr1-xCaxMnO3 中两阶段光致绝缘体-金属转变的作用谱
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
Y. Tokura
中科院分区：
文献类型：
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作者：
M. Fiebig;K. Miyano;T. Satoh;Y. Tomioka;Y. Tokura
在 ${mathrm{Pr}}_{1ensuremath{-}x}{mathrm{Ca}}_{x}{mathrm{MnO}}_{3}$ 中光致绝缘体-金属转变的作用光谱在 $0.45ensuremath{-}3.05 mathrm{eV}$ 范围内进行研究。跃迁的光子密度阈值在 $ensuremath{sim}0.4 mathrm{eV}$ 处表现出带隙行为，具有各向异性特征，并且对载流子掺杂程度 x 不敏感。建议采用两阶段机制进行过渡。在第一阶段，光激发的电荷载流子通过屏蔽效应熔化电荷有序态，随后局部形成亚稳态金属域。在第二阶段，金属域之间的势垒被施加的电场克服，从而形成只要电流保持就保持稳定的连续导电路径。
The action spectra for the photoinduced insulator-metal transition in ${mathrm{Pr}}_{1ensuremath{-}x}{mathrm{Ca}}_{x}{mathrm{MnO}}_{3}$ were investigated in the $0.45ensuremath{-}3.05 mathrm{eV}$ range. The photon-density threshold for the transition exhibits a gaplike behavior at $ensuremath{sim}0.4 mathrm{eV}$ 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.