Department of Physics, Hanyang University, Seoul, 04763, Korea.
Department of Physics, Boston College, Chestnut Hill, Massachusetts, 02367, USA.
Sci Rep. 2017 Sep 5;7(1):10494. doi: 10.1038/s41598-017-10725-z.
We report on infrared spectroscopy experiments on the electronic response in (Sr La )IrO (x = 0, 0.021, and 0.067). Our data show that electron doping induced by La substitution leads to an insulator-to-metal transition. The evolution of the electronic structure across the transition reveals the robustness of the strong electronic correlations against the electron doping. The conductivity data of the metallic compound show the signature of the pseudogap that bears close similarity to the analogous studies of the pseudogap in the underdoped cuprates. While the low energy conductivity of the metallic compound is barely frequency dependent, the formation of the pseudogap is revealed by the gradual suppression of the featureless conductivity below a threshold frequency of about 17 meV. The threshold structure develops below about 100 K which is in the vicinity of the onset of the short-range antiferromagnetic order. Our results demonstrate that the electronic correlations play a crucial role in the anomalous charge dynamics in the (Sr La )IrO system.
我们报告了（SrLa）IrO（x=0、0.021 和 0.067）中电子响应的红外光谱实验。我们的数据表明，La 取代引起的电子掺杂导致了绝缘到金属的转变。在转变过程中电子结构的演化揭示了强电子关联对电子掺杂的稳健性。金属化合物的电导率数据显示了赝能隙的特征，与类似的欠掺杂铜酸盐中赝能隙的研究非常相似。虽然金属化合物的低能电导率几乎不依赖于频率，但在约 17meV 的阈值频率以下，无特征的电导率逐渐抑制，揭示了赝能隙的形成。阈值结构在约 100K 以下发展，这接近短程反铁磁序的开始。我们的结果表明，电子关联在（SrLa）IrO 体系中的异常电荷动力学中起着至关重要的作用。
