| Summary: | To understand the influence of doping Sr atoms on the structural, magnetic, and electronic properties of the infinite-layer NdSrNiO<sub>2</sub>, we carried out the screened hybrid density functional study on the Nd<sub>9-<i>n</i></sub>Sr<i><sub>n</sub></i>Ni<sub>9</sub>O<sub>18</sub> (<i>n</i> = 0–2) unit cells. Geometries, substitution energies, magnetic moments, spin densities, atom- and lm-projected partial density of states (PDOS), spin-polarized band structures, and the average Bader charges were studied. It showed that the total magnetic moments of the Nd<sub>9</sub>Ni<sub>9</sub>O<sub>18</sub> and Nd<sub>8</sub>SrNi<sub>9</sub>O<sub>18</sub> unit cells are 37.4 and 24.9 emu g<sup>−1</sup>, respectively. They are decreased to 12.6 and 4.2 emu g<sup>−1</sup> for the Nd<sub>7</sub>Sr<sub>2</sub>Ni<sub>9</sub>O<sub>18</sub>-Dia and Nd<sub>7</sub>Sr<sub>2</sub>Ni<sub>9</sub>O<sub>18</sub>-Par unit cells. The spin density distributions demonstrated that magnetic disordering of the Ni atoms results in the magnetism decrease. The spin-polarized band structures indicated that the symmetry of the spin-up and spin-down energy bands around the Fermi levels also influence the total magnetic moments. Atom- and <i>lm</i>-projected PDOS as well as the band structures revealed that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Ni</mi><mo stretchy="false">(</mo><msub><mi>d</mi><mrow><msup><mi>x</mi><mn>2</mn></msup><mo>−</mo><msup><mi>y</mi><mn>2</mn></msup></mrow></msub><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> is the main orbital intersecting the Fermi level. As a whole, electrons of Sr atoms tend to locate locally and hybridize weakly with the O atoms. They primarily help to build the infinite-layer structures, and influence the electronic structure near the Fermi level indirectly.
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