Half-metallic ferromagnetic/ferrimagnetic (FiM) materials are a matter of enormous interest due to their potential technological applications in solid-state electronic devices. In this way, strain plays an important role to tune or control the physical properties of the systems; therefore, the influence of both biaxial ([110]) and hydrostatic ([111]) strain on the electronic and magnetic properties of recently synthesized double perovskite oxide Lu₂NiIrO₆ is investigated using density-functional theory calculations. The unstrained system exhibits a FiM Mott-insulating (i.e., having an energy gap of 0.20 eV) ground state due to strong antiferromagnetic superexchange coupling between high-energy half-filled Ni²⁺–e²_g↑ and low-energy partially filled Ir⁴⁺ t³_2g↑t²_2g↓ orbitals. Interestingly, a half-metallic FiM state is predicted under biaxial and hydrostatic compressive strains of −8% and −6%, respectively. The admixture of Ir 5d orbitals in the spin-majority channel is mainly responsible for the conductivity with small contributions from Ni 3d orbitals. In contrast, all the tensile strain systems show almost the same electronic behavior (Mott-insulating FiM states) as found in the case of the unstrained system. The magnetic moments of the Ni (Ir) ion slightly decrease and increase as a function of compressive and tensile strains due to shortening and lengthening of the Ni–O(Ir–O) bond lengths, respectively. Moreover, our calculations show that compressive strain enhances the structural distortions, which could help to increase the Curie temperature of the system.

中文翻译：

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亚铁磁Mott绝缘子Lu2NiIrO6中的应变驱动半金属性：第一性原理。

半金属铁磁/亚铁磁（FiM）材料由于在固态电子设备中的潜在技术应用而备受关注。通过这种方式，应变在调整或控制系统的物理属性中起着重要的作用。因此，使用密度泛函理论计算研究了双轴（[110]）和静水（[111]）应变对最近合成的双钙钛矿氧化物Lu ₂ NiIrO ₆的电子和磁性的影响。由于高能半填充Ni ²⁺ -e ²之间的强反铁磁超交换耦合，未应变系统表现出FiM Mott绝缘（即，具有0.20 eV的能隙）基态。_g ↑和低能量部分填充Ir ⁴⁺ t ³ _2g ↑t ² _2g↓轨道。有趣的是，在双轴和静水压应变分别为-8％和-6％的情况下，预测了半金属的FiM状态。Ir 5d轨道在自旋占主导地位的通道中的混合主要是由于Ni 3d轨道对电导率的贡献很小。相反，所有拉伸应变系统都表现出与未应变系统几乎相同的电子行为（莫特绝缘FiM状态）。Ni（Ir）离子的磁矩分别由于Ni–O（Ir–O）键长的缩短和延长而随压缩应变和拉伸应变而略有下降和增加。此外，我们的计算结果表明，压缩应变会增加结构变形，从而有助于提高系统的居里温度。