Kim Bongjae, Kim Beom Hyun, Kim Kyoo, Min B I
Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea.
MPPC CPM, Pohang University of Science and Technology, Pohang, 37673, Korea.
Sci Rep. 2016 Jun 3;6:27095. doi: 10.1038/srep27095.
We have systematically investigated substrate-strain effects on the electronic structures of two representative Sr-iridates, a correlated-insulator Sr2IrO4 and a metal SrIrO3. Optical conductivities obtained by the ab initio electronic structure calculations reveal that the tensile strain shifts the optical peak positions to higher energy side with altered intensities, suggesting the enhancement of the electronic correlation and spin-orbit coupling (SOC) strength in Sr-iridates. The response of the electronic structure upon tensile strain is found to be highly correlated with the direction of magnetic moment, the octahedral connectivity, and the SOC strength, which cooperatively determine the robustness of Jeff = 1/2 ground states. Optical responses are analyzed also with microscopic model calculation and compared with corresponding experiments. In the case of SrIrO3, the evolution of the electronic structure near the Fermi level shows high tunability of hole bands, as suggested by previous experiments.
我们系统地研究了衬底应变对两种具有代表性的锶铱酸盐（一种关联绝缘体Sr2IrO4和一种金属SrIrO3）电子结构的影响。通过从头算电子结构计算得到的光导率表明，拉伸应变使光学峰位置向高能侧移动且强度改变，这表明锶铱酸盐中电子关联和自旋轨道耦合（SOC）强度增强。发现拉伸应变作用下电子结构的响应与磁矩方向、八面体连通性以及SOC强度高度相关，它们共同决定了总角动量J=1/2基态的稳定性。还通过微观模型计算分析了光学响应，并与相应实验进行了比较。在SrIrO3的情况下，费米能级附近电子结构的演化显示出空穴带具有高度可调性，正如先前实验所表明的那样。
