Polarity-induced electronic and atomic reconstruction at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>NdNiO</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> interfaces
Ri He, Peiheng Jiang, Yi Lu, Yidao Song, Mingxing Chen, Mingliang Jin, Lingling Shui, Zhicheng Zhong
Abstract
Superconductivity has recently been observed in Sr-doped ${\mathrm{NdNiO}}_{2}$ films grown on ${\mathrm{SrTiO}}_{3}$. Whether it is caused by or related to the interface remains an open question. To address this issue, we use density-functional theory calculation and charge-transfer self-consistent model to study the effects of polar discontinuity on the electronic and atomic reconstruction at the ${\mathrm{NdNiO}}_{2}/{\mathrm{SrTiO}}_{3}$ interface. We find that sharp interface with pure electronic reconstruction only is energetically unfavorable, and atomic reconstruction is unavoidable. We further propose a possible interface configuration that contain residual apical oxygen. These oxygen atoms lead to hybrids of ${d}_{{z}^{2}}$ and ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ states at the Fermi level, which weaken the single-band feature and may be detrimental to superconductivity.