论文标题
孔掺杂的氧化物ATIO_2H（A = K，RB，CS）自发极化和超导性的共存：第一原理研究
Coexistence of spontaneous polarization and superconductivity in hole-doped oxyhydrides ATiO_2H (A=K, Rb, Cs): first-principles study
论文作者
论文摘要
极性金属是一种具有极性变形和金属性的材料。如果超导体，这种材料有望显示出异国情调的磁电现象。在这里，我们从理论上探索一系列钙钛矿型氧化物含氧式氧化物ATIO $ _2 $ H（A = K，RB，CS）在孔掺杂条件下，使用基于密度密度函数理论的FirstPrinciples计算，在孔掺杂条件下探索了铁电和超导体。我们的模拟表明，这些化合物在最佳掺杂浓度下宿主自发极化和超导性。超导性和较大极化（〜100 $ $ $ c/cm $^2 $）的异常共存起源于极性失真和超导状态的弱耦合，其原因是位移原子和空间限制的金属载体的分离。此外，Valence Band最大值附近的独特电子性能增强了超导性：四分之一的带状分散，具有相当大的氢1S状态。因此，我们的研究以氧化物为可能的模型极性超导系统，该系统可能可用于将来的磁电动器件。
The polar metal is a material that hosts both polar distortion and metallicity. Such a material is expected to show exotic magneto-electric phenomena if superconducts. Here, we theoretically explore ferroelectric and superconducting properties in a series of perovskite-type oxyhydrides ATiO$_2$H (A=K, Rb, Cs) under hole-doping conditions using the first-principles calculations based on the density functional theory. Our simulation shows that these compounds host spontaneous polarization and superconductivity at optimal doping concentration. The unusual coexistence of superconductivity and large polarization (~100 $μ$C/cm$^2$) originates from weak coupling of the polar distortion and superconducting states, the reason of which is separation of the displaced atoms and spacially confined metallic carriers. Besides, the superconductivity is enhanced by the unique electronic properties near the valence band maximum: quartic band dispersion with a sizable contribution of hydrogen 1s states. Our study thus feature the oxyhydrides as possible model polar superconducting systems, which may be utilizable for future magneto-electric devices.
