论文标题
三层方形平面镍盐中超导性的理论研究
Theoretical investigation of superconductivity in trilayer square-planar nickelates
论文作者
论文摘要
在SR掺杂的NDNIO $ _ {2} $中发现超导性是对具有与粉结酸盐类似的电子和磁性特性的镍氧化物材料长期追求的至关重要的突破。 ndnio $ _2 $是带有通用化学配方r $ $ $ _ {n+1} $ ni $ _n $ _n $ o $ $ o $ _ {2n+2} $的一组平面镍家族的无限层成员。在这封信中，我们使用第一原理和$ t-j $模型计算的组合研究了该系列的三层成员的超导率（r $ _4 $ ni $ _3 $ o $ _8 $）。 R$_4$Ni$_3$O$_8$ compounds resemble cuprates more than RNiO$_2$ materials in that only Ni-$d_{x^{2}-y^{2}}$ bands cross the Fermi level, they exhibit a largely reduced charge transfer energy, and as a consequence superexchange interactions are significantly enhanced.我们发现，掺杂的R $ _4 $ ni $ _3 $ _3 $ _8 $ _8 $化合物中的超导不稳定更强，最大差距大约是SR $ _ {0.2} $ _ nd $ _ {0.8} $ nio $ _2 $ _2 $的SR $ _ {0.2} $ _ ND $ _ ND} $ _2 $。
The discovery of superconductivity in Sr-doped NdNiO$_{2}$ is a crucial breakthrough in the long pursuit for nickel oxide materials with electronic and magnetic properties similar to those of the cuprates. NdNiO$_2$ is the infinite-layer member of a family of square-planar nickelates with general chemical formula R$_{n+1}$Ni$_n$O$_{2n+2}$ (R = La, Pr, Nd, $n= 2, 3, ... \infty$). In this letter, we investigate superconductivity in the trilayer member of this series (R$_4$Ni$_3$O$_8$) using a combination of first-principles and $t-J$ model calculations. R$_4$Ni$_3$O$_8$ compounds resemble cuprates more than RNiO$_2$ materials in that only Ni-$d_{x^{2}-y^{2}}$ bands cross the Fermi level, they exhibit a largely reduced charge transfer energy, and as a consequence superexchange interactions are significantly enhanced. We find that the superconducting instability in doped R$_4$Ni$_3$O$_8$ compounds is considerably stronger with a maximum gap about four times larger than that in Sr$_{0.2}$Nd$_{0.8}$NiO$_2$.
