Metal-to-insulator transition in SmNiO3 induced by chemical doping: a first principles study†,Molecular Systems Design & Engineering

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Metal-to-insulator transition in SmNiO3 induced by chemical doping: a first principles study†
Molecular Systems Design & Engineering ( IF 3.2 ) Pub Date : 2018-01-11 00:00:00 , DOI: 10.1039/c8me00002f
Pilsun Yoo _{1,

2,

3,

4} , Peilin Liao _{1,

2,

3,

4}

Affiliation

Rare-earth perovskite RNiO₃ (R = Sm, Pr, Nd, etc.) has been investigated during the past decades due to a variety of tunable physical properties such as electrical conductivity and optical properties. Chemical doping in SmNiO₃ was confirmed by experiments as a new way to drive metal-to-insulator transition under isothermal conditions. However, detailed crystal and electronic structure changes remain unknown. Here, we applied first principles density functional theory (DFT) to understand the mechanism of chemical doping with H and Li in SmNiO₃. We showed that the DFT+U method with the PBEsol functional and U_eff = 2 eV produced results in good agreement with experiments for both insulating and metallic phases of SmNiO₃. We examined the changes in geometry and electronic structures at various hydrogen and lithium doping concentration up to the experimental 1 : 1 H(Li) : Ni ratio. We observed a band gap opening of ∼3.0 eV (predicted by HSE06) at H : Ni = 1 : 1, in good agreement with experiments. We further investigated the migration of H or Li along the [001] direction of SmNiO₃. We found a migration barrier of ∼0.3 eV for hydrogen and ∼0.4 eV for lithium. These current findings pave the way for future theoretical and experimental investigation to develop efficient metal–insulator switching devices using rare earth perovskites.

中文翻译：

化学掺杂在SmNiO _3中金属向绝缘体的转变：第一个原理研究†

过去数十年来，由于各种可调节的物理性质（如电导率和光学性质），已经对稀土钙钛矿RNiO ₃（R = Sm，Pr，Nd等）进行了研究。实验证实了SmNiO _3中的化学掺杂是在等温条件下驱动金属向绝缘体转变的一种新方法。但是，详细的晶体和电子结构变化仍然未知。在这里，我们应用第一原理密度泛函理论（DFT）来了解SmNiO _3中H和Li的化学掺杂机理。我们证明了具有PBEsol功能和U _eff的DFT + U方法等于2 eV的结果与SmNiO _3的绝缘相和金属相的实验结果吻合良好。我们研究了在各种氢和锂掺杂浓度下，直至实验的1：1 H（Li）：Ni比，几何结构和电子结构的变化。我们观察到在H：Ni = 1：1时〜3.0 eV的带隙开口（由HSE06预测），与实验吻合良好。我们进一步研究了H或Li在SmNiO ₃的[001]方向上的迁移。我们发现氢的迁移势垒为〜0.3 eV，锂的迁移势垒为〜0.4 eV。这些最新发现为未来的理论和实验研究铺平了道路，以开发使用稀土钙钛矿的高效金属-绝缘体开关设备。

更新日期：2018-01-11

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