ABSTRACT Recently, previous studies have shown that at room temperature, EuNbO3 adopts an orthorhombic structure of Imma space group with a ferromagnetic behaviour. The relevant idea of ⁣this work is to provide a new insight into some electronic and magnetic behaviours of EuNbO3 in orthorhombic structure, which are still unknown, based on the results already found previously. The structural properties have been determined using two functionals (GGA-PBE and GGA-PBEsol) and the found results are in good agreement with the previous ones. Mechanical behaviour and elastic anisotropy have also been studied in detail from which, it has been confirmed that EuNbO3 is mechanically stable in Imma orthorhombic perovskite structure. The directional analysis of Young’s modulus has shown that it is elastically anisotropic. For the electronic properties, many approaches have been used in order to take all the considerations that are not taken into account by GGA semilocal functional, hence, spin–orbit coupling effect (SOC), Hubbard correction (GGA + U) and Modified Becke–Johnson exchange potential (mBJ) have been adopted. The two adopted mBJ parameterizations gave different results, hence, for that of TB-mBJ, the studied compound is almost halfmetallic, while that of Radi A. Jishi et al. showed a semiconductor behaviour. To estimate Curie temperature, we have employed the mean field approximation (MFA), hence, its estimated value is higher than that of transition to the tetragonal I4/mcm structure, which has been determined previously. The ionic character of Eu-O and Nb-O bonds has been confirmed by The Quantum Theory of Atoms in Molecules (QTAIM).

中文翻译：

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正交结构中铁磁铌酸铕 EuNbO3 的弹性各向异性、电子和磁行为：DFT + U、MFA 和 QTAIM 研究

摘要 最近，先前的研究表明，在室温下，EuNbO3 采用具有铁磁行为的 Imma 空间群的正交结构。这项工作的相关思想是基于先前已经发现的结果，提供对正交结构中 EuNbO3 的一些电子和磁行为的新见解，这些行为仍然未知。使用两种泛函（GGA-PBE 和 GGA-PBEsol）确定了结构特性，发现的结果与之前的结果非常吻合。还详细研究了机械行为和弹性各向异性，从中证实 EuNbO3 在 Imma 斜方晶钙钛矿结构中具有机械稳定性。杨氏模量的方向分析表明它是弹性各向异性的。对于电子特性，已经使用了许多方法来考虑 GGA 半局域泛函未考虑的所有因素，因此，自旋轨道耦合效应 (SOC)、哈伯德校正 (GGA + U) 和修正贝克-约翰逊交换势 (mBJ) ) 已被采用。两种采用的 mBJ 参数化给出了不同的结果，因此，对于 TB-mBJ 而言，所研究的化合物几乎是半金属的，而 Radi A. Jishi 等人的研究化合物。表现出半导体行为。为了估计居里温度，我们采用了平均场近似（MFA），因此，它的估计值高于之前确定的向四方 I4/mcm 结构转变的估计值。Eu-O 和 Nb-O 键的离子特性已被分子中原子的量子理论 (QTAIM) 证实。