Hydrogen-induced insulating state accompanied by interlayer charge ordering in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">SmNiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>
Kunihiko Yamauchi, Ikutaro Hamada
Abstract
The effect of hydrogen doping on the crystal structure and the electronic state of ${\mathrm{SmNiO}}_{3}$ is investigated by means of density functional theory with a combinatorial structure-generation approach. While 100% of hydrogen doping per Ni atom has been supposed to be responsible for the experimentally observed insulating phase, we found that 50% of hydrogen doping results in an outstandingly stable atomic structure showing the insulating property after the structural relaxation was performed while imposing a ferromagnetic configuration. The stable crystal structure shows the peculiar layered pattern of charge disproportionation of ${\mathrm{Ni}}^{2+}$ and ${\mathrm{Ni}}^{3+}$ valences together with the strong Jahn-Teller distortion that causes the ${e}_{g}$ orbital state splitting and opens the band gap.