Based on ab initio calculations of the ground state energy as a function of volume E(V) and thermodynamic model of the crystal lattice, we study the role of phonon anharmonicity in the formation of a complex of thermal and elastic properties of UGe₂. In the framework of the developed model, an explanation is given for the first time of the experimentally observed abnormal growth of the bulk modulus of UGe₂ as a function of temperature. The reassessment of the lattice anharmonicity parameters led to an indication of a significant contribution of optical phonons to the thermal expansion coefficient (CTE) of UGe₂, which has not been considered previously. Taking this contribution into account leads to the conclusion that there is a negative non-lattice component of the CTE not only in the region of magnetic ordering but also above the Curie temperature, which indicates the effects of short-range magnetic order.

基于基态能量与体积E（V）的函数的从头算计算以及晶格的热力学模型，我们研究了声子非谐性在UGe ₂热和弹性性质复合物中的作用。在开发模型的框架中，首次给出了实验观察到的UGe ₂体积模量随温度的异常增长的解释。晶格非谐性参数的重新评估表明，光子对UGe ₂的热膨胀系数（CTE）有重要贡献，以前没有考虑过。考虑到这一贡献，得出的结论是，CTE不仅在磁有序区域而且在居里温度以上都具有负的非晶格成分，这表明了短程磁有序的影响。