应变Sr $_2$ CoIrO $_6$双钙钛矿中的电子重构和电荷转移
Electronic reconstruction and charge transfer in strained Sr$_2$CoIrO$_6$ double perovskite
摘要：
在密度泛函理论（DFT）的框架下，结合对外延薄膜的吸收光谱测量，研究了双轴应变下双钙钛矿结构SrPDMATHABMM CoIrOPDMATHABMN（SCIO）的电子、磁性和光学性质.虽然端部成员SrIrO $_3$是具有淬灭自旋和轨道矩的半金属，并且体SrCoO $_3$是具有分别为2.50和0.13 $μ_{B}$的自旋和轨道矩的铁磁（FM）金属，但是双钙钛矿SCIO作为反铁磁Mott绝缘体出现，其中Co、Ir平面沿着[110]方向反平行排列。Co的自旋和增强轨道矩分别为$\sim 2.35-2.45$和$0.31-$ 0.45 $μ_{B}$。最值得注意的是，Ir获得了显著的自旋和轨道矩，分别为1.21 - 1.25和0.13 $μ_{B}$。轨道占据的分析表明，由于大量的电荷转移，从少数到多数自旋状态的Ir和从Ir到Co的电子重建，发出信号的Ir $^{4+δ}$，Co $^{4-δ}$配置。双轴应变从-1.02%（$a_{\rm NdGaO_3}$）到0%（$a_{\rm SrTiO_3}$）到1.53%（$a_{\rm GdScO_3}$）变化，影响$t_{2g}$态的轨道极化并导致带隙在163和235 meV之间的非单调变化。吸收系数显示出两个平台的特征，这是由于从价态到较低的窄$t_{2g}$带和较高的宽$e_{g}$带的跃迁。包括许多体效应，特别是激子效应，通过求解Bethe-Salpeter方程（BSE），通过$\sim0.2$增加了带隙，并提高了与测量光谱的一致性，所述测量光谱关于$\sim 2.6$ eV处的第二峰的位置。
英文摘要：
The electronic, magnetic and optical properties of the double perovskite Sr$_2$CoIrO$_6$ (SCIO) under biaxial strain are explored in the framework of density functional theory (DFT) including a Hubbard $U$ term and spin-orbit coupling (SOC) in combination with absorption spectroscopy measurements on epitaxial thin films. While the end member SrIrO$_3$ is a semimetal with a quenched spin and orbital moment and bulk SrCoO$_3$ is a ferromagnetic (FM) metal with spin and orbital moment of 2.50 and 0.13 $μ_{B}$, respectively, the double perovskite SCIO emerges as an antiferromagnetic Mott insulator with antiparallel alignment of Co, Ir planes along the [110]-direction. Co exhibits a spin and enhanced orbital moment of $\sim 2.35-2.45$ and $0.31-$0.45 $μ_{B}$, respectively. Most remarkably, Ir acquires a significant spin and orbital moment of 1.21-1.25 and 0.13 $μ_{B}$, respectively. Analysis of the orbital occupation indicates an electronic reconstruction due to a substantial charge transfer from minority to majority spin states in Ir and from Ir to Co, signaling an Ir$^{4+δ}$, Co$^{4-δ}$ configuration. Biaxial strain, varied from -1.02% ($a_{\rm NdGaO_3}$) through 0% ($a_{\rm SrTiO_3}$) to 1.53% ($a_{\rm GdScO_3}$), influences in partcular the orbital polarization of the $t_{2g}$ states and leads to a nonmonotonic change of the band gap between 163 and 235 meV. The absorption coefficient reveals a two plateau fearure due to transitions from the valence to the lower lying narrow $t_{2g}$ and the higher lying broader $e_{g}$ bands. Inclusion of many body effects, in particular, excitonic effects by solving the Bethe-Salpeter equation (BSE), increases the band gap by $\sim0.2$ and improves the agreement with the measured spectrum concerning the position of the second peak at $\sim 2.6$ eV.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
