论文标题
无限层镍中掺杂载体的轨道和旋转特征
Orbital and Spin Character of Doped Carriers in Infinite-Layer Nickelates
论文作者
论文摘要
ND $ _ {1-x} $ sr $ _ {x} $ nio $ _2 $的最新发现在现场引起了极大的关注。一个关键的开放问题对电子结构的演变相对于孔掺杂。在这里，我们利用X射线吸收光谱（XAS）和共振非弹性X射线散射（RIX）来探测NiO $ _2 $ planes的掺杂依赖性电子结构。掺杂后，除了主要吸收峰外，Ni $ l_3 $ edge XAS中的较高能量功能还会发展出来。通过将我们的数据与原子多重计算进行比较，包括$ d_ {4h} $ Crystal Field，掺杂诱导的功能与$ d^8 $旋转单重线状态一致，其中掺杂的孔位于$ d_ {x^2-y^2} $ orbitals中，与掺杂的单个Band Hubbard模型相似。在RIXS光谱中观察到的轨道激发进一步支持，该光谱在掺杂时软化，以与$ d_ {x^2-y^2} $ orbital中的孔增加相关的费米水平移动来证实。
The recent discovery of superconductivity in Nd$_{1-x}$Sr$_{x}$NiO$_2$ has drawn significant attention in the field. A key open question regards the evolution of the electronic structure with respect to hole doping. Here, we exploit x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) to probe the doping dependent electronic structure of the NiO$_2$ planes. Upon doping, a higher energy feature in Ni $L_3$ edge XAS develops in addition to the main absorption peak. By comparing our data to atomic multiplet calculations including $D_{4h}$ crystal field, the doping induced feature is consistent with a $d^8$ spin singlet state, in which doped holes reside in the $d_{x^2-y^2}$ orbitals, similar to doped single band Hubbard models. This is further supported by orbital excitations observed in RIXS spectra, which soften upon doping, corroborating with Fermi level shift associated with increasing holes in the $d_{x^2-y^2}$ orbital.
