发表机构
ETH Zurich; Université de Liège（苏黎世联邦理工学院; 列日大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过DFT计算发现SmNiO$_3$/BaTiO$_3$超晶格中电荷歧化重排可屏蔽极性不连续性，转移1 e/f.u.并改变Ni价态序列，该机制可能普遍适用于钙钛矿体系。
AI 中文摘要
我们使用密度泛函理论（DFT）证明电荷歧化的重新排列是异质界面处极性不连续性屏蔽的一种新机制。我们聚焦于SmNiO$_3$，一种III-III钙钛矿，其特征是源于Ni位点电子歧化的绝缘基态。当与铁电II-IV钙钛矿BaTiO$_3$界面接触时，该系统可表现出极性不连续性，其大小由界面性质（NiO$_2$-BaO或SmO-TiO$_2$）和BaTiO$_3$自发极化方向决定。在使界面电荷最大化的取向下，SmNiO$_3$通过在两个界面之间转移1 $e$/f.u.并改变歧化序列来补偿，从Ni$^{4+}$/Ni$^{2+}$变为SmO-TiO$_2$界面处的Ni$^{2+}$/Ni$^{2+}$和NiO$_2$-BaO界面处的Ni$^{4+}$/Ni$^{4+}$。虽然该机制在所有表现出电荷歧化的钙钛矿中可能具有普遍性，但我们对BiNiO$_3$/BaTiO$_3$超晶格的正式分析表明，较大的极性不连续性可能需要更复杂的歧化模式来屏蔽。
英文摘要
We use density functional theory (DFT) to demonstrate rearrangement of charge disproportionation as a new mechanism for screening polar discontinuities at heterointerfaces. We focus on SmNiO$_3$, a III-III perovskite characterized by an insulating ground state that originates from disproportionation of the electrons at the Ni sites. When interfaced with ferroelectric, II-IV perovskite BaTiO$_3$, this system can display a polar discontinuity whose magnitude is determined by the nature of the interface (NiO$_2$-BaO or SmO-TiO$_2$) and the orientation of the BaTiO$_3$ spontaneous polarization. In the orientation maximizing the interface charge, SmNiO$_3$ compensates by transferring 1 $e$/f.u. between the two interfaces and modifying the disproportionation sequence from Ni$^{4+}$/Ni$^{2+}$ to Ni$^{2+}$/Ni$^{2+}$ at the SmO-TiO$_2$ interface and to Ni$^{4+}$/Ni$^{4+}$ at the NiO$_2$-BaO interface. While this mechanism is potentially universal in all perovskites exhibiting charge disproportionation, our formal analysis of BiNiO$_3$/BaTiO$_3$ superlattices suggests that larger polar discontinuities may need more complex disproportionation patterns for screening.
