高熵陶瓷展现出广阔的应用前景，但稀土掺杂对其影响尚不清楚。本工作采用密度泛函理论研究了Er掺杂对(Ti_0.25Ta_0.25Hf_0.25Nb_0.25-xEr_x)₂Zr₂O₇ (x = 0~0.25)高熵陶瓷结构、力学、电子及位错性质的影响。采用2 × 2 × 2特殊准随机结构模型模拟无序超晶胞，计算了形成焓、晶格畸变、弹性常数、力学性能和态密度等关键参数，以阐明Er掺杂的影响机制。结果表明，Er取代Nb位可获得最低的形成焓，从而实现最佳的结构稳定性。随着Er含量的增加，晶格畸变加剧，表现为原子尺寸差异和均方根原子位移的增加。(Ti_0.25Ta_0.25Hf_0.25Nb_0.1875Er_0.0625)₂Zr₂O₇ (x = 6.25%)和(Ti_0.25Ta_0.25Hf_0.25Nb_0.0625Er_0.1875)₂Zr₂O₇ (x = 18.75%)高熵陶瓷表现出峰值体积模量、Young’s模量、剪切模量、断裂韧性和位错能量因子。Er含量越高，韧性越差，而当Er含量达到18.75%时，各向同性增强，各向异性减弱。Er掺杂可提高Fermi能级的态密度，从而增强金属和电导特性。螺位错的能量因子低于刃位错，有助于螺位错形核。当Er含量达到18.75%时，刃位错宽度达到峰值，从而促进孪生变形并提高塑性。

High-entropy ceramics (HECs) are promising materials for advanced applications; however, the effects of rare-earth doping on their structural and mechanical properties remain underexplored. Using density functional theory, this study investigates the effects of Er doping on the structural, mechanical, electronic, and dislocation properties of (Ti_0.25Ta_0.25Hf_0.25Nb_0.25-xEr_x)₂Zr₂O₇ (x = 0%–25%) HECs. The disordered ceramic supercell is modeled as a 2 × 2 × 2 special quasirandom structure. The influencing mechanisms of Er doping are elucidated by calculating the critical parameters (formation enthalpy, lattice distortion, elastic constants, mechanical properties, and density of states). Er substitution at the Nb sites minimizes the formation enthalpy, i.e., optimizes the structural stability. Increasing the Er content intensifies the lattice distortion, as evidenced by increased atomic size differences and root-mean-square atomic displacements. The (Ti_0.25Ta_0.25Hf_0.25Nb_0.1875Er_0.0625)₂Zr₂O₇ (x = 6.25%) and (Ti_0.25Ta_0.25Hf_0.25Nb_0.0625Er_0.1875)₂Zr₂O₇ (x = 18.75%) HECs exhibit the highest bulk modulus, Young’s modulus, shear modulus, fracture toughness, and dislocation energy factors. The ductility decreases with an increase in Er content. Moreover, the isotropy increases and anisotropy decreases with an increase in Er content up to 18.75%. Er doping elevates the density of states at the Fermi level, enhancing the metallic and electrical conductivity properties of the HECs. The energy factors are lower at screw dislocations than at edge dislocations, aiding the nucleation of screw dislocations. The edge-dislocation width peaks at 18.75% Er, promoting twinning deformation and improving the plasticity.