Investigation of insulator-metal transition in Ti4O7 using terahertz probe pulse
Investigation of insulator-metal transition in Ti4O7 using terahertz probe pulse
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DOI：
10.1063/1.4942602
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发表时间：
2016-02
影响因子：
4
通讯作者：
H. Kamioka;J. Nishitani;Hiroyuki Tsukada;Ryotaro Yamaguchi;T. Suemoto
中科院分区：
文献类型：
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作者：
H. Kamioka;J. Nishitani;Hiroyuki Tsukada;Ryotaro Yamaguchi;T. Suemoto
用光泵太赫兹(THz)探测技术研究了Ti4O7单晶在不同激发密度下的超快光诱导绝缘体-金属相变。在130K时，氧化物呈现出从低温相到中间相和在150K时从高温金属相到中间相的两步相变。低温相的光照射导致THz探头的透过率在3.6ps内超快下降，相当于金属电畴的产生。当激励高于阈值水平时，紧随其后的是额外的缓慢下降。振幅和寿命对激发密度的非线性依赖关系表明，金属磁畴自发生长，并根据它们的生成量而稳定。
The ultrafast photo-induced insulator-metal transition in a Ti4O7 single crystal is investigated with different excitation densities using an optical-pump terahertz (THz)-probe technique. The oxide shows a two-step phase transition at 130 K from a low temperature (LT) phase to an intermediate phase and to a high temperature metallic phase at 150 K. The photo-irradiation in the LT phase induces an ultrafast decrease in the transmittance of the THz probe within 3.6 ps, corresponding to the generation of a metallic domain. This is followed by an additional slow decrease when the excitation is above the threshold level. The nonlinear dependence of the amplitude and lifetime on the excitation density indicates that the metallic domains grow spontaneously and are stabilized depending on their resultant amount.