论文标题
srmoo $ _3 $/srtio $ _3 $ superlattices中的隐藏梯子：实验和理论计算
Hidden Ladder in SrMoO$_3$/SrTiO$_3$ Superlattices: Experiments and Theoretical Calculations
论文作者
论文摘要
双层钙钛矿氧化物SR $ _3 $ MO $ _2 $ o $ _7 $被认为是一种“隐藏阶梯”系统，其宽阔和狭窄的乐队在费米级附近，预计会为此高。然而，合成的困难，尤其是在制备没有氧不足的样品时，可能会阻碍观察到超导性。在这项研究中，我们通过人工超级晶格构建了一个双层SRMOO $ _3 $块，并使用绝缘srtio $ _3 $块（（srmoo $ _3 $）$ _ m $/（srtio $ _3 $ _3 $ _3 $）$ _ t $ _ m $ _ m $ _ m $ _ t $（$ m = 2，4 $ t = 4 $; $ t = 4 $）。双层SRMOO $ _3 $（$ M = 2 $）的第一原理计算展示了Fermi级别附近的宽核乐队结构，该结构与Sr $ $ _3 $ MO $ $ _2 $ o $ o $ _7 $非常相似。通过增加srtio $ _3 $ layers $ t $的数量，沿$ k_z $方向的分散体强烈压制。然而，未观察到下降到0.1K。我们根据扫描透射电子显微镜和带状结构计算的结果讨论了本膜的超导性。
A double-layered perovskite oxide Sr$_3$Mo$_2$O$_7$ is considered a "hidden ladder" system with wide and narrow bands near the Fermi level, for which high-$T_{\rm c}$ superconductivity is expected. However, the difficulty in synthesis, especially in the preparation of samples without oxygen deficiency, can hinder the observation of superconductivity. In this study, we constructed a double-layer SrMoO$_3$ block through artificial superlattices with the insulating SrTiO$_3$ block, (SrMoO$_3$)$_m$/(SrTiO$_3$)$_t$ ($m = 2, 4$; $t = 4$). First-principles calculations for bilayered SrMoO$_3$ ($m = 2$) exhibit a wide-narrow band structure near the Fermi level, which bears a close resemblance to Sr$_3$Mo$_2$O$_7$. The dispersion along the $k_z$ direction is strongly suppressed by increasing the number of the SrTiO$_3$ layers, $t$. However, no superconductivity is observed down to 0.1 K. We discuss the absence of the superconductivity for the present films on the basis of results of scanning transmission electron microscopy and band structure calculations.
