中文摘要：

利用基于密度泛函理论的第一性原理系统地研究了5d过渡金属二硼化物TMB2 （TM=Hf–Au） 的结构、热学、力学和电学性质. 我们考虑了三种结构, 分别为AlB2, ReB2和WB2结构. 计算得到的晶格常数与先前的理论和实验研究符合得很好. 通过计算生成焓预测了化合物的热力学稳定性; 从HfB2到AuB2, 生成焓的整体趋势是逐渐增加的. 在所考虑的结构中, 对HfB2和TaB2, AlB2结构是最稳定的; 对WB2, ReB2, OsB2, IrB2和AuB2, ReB2结构是最稳定的; 对PtB2, WB2结构是最稳定的. 在所考虑的化合物中, ReB2结构的ReB2具有最大的剪切模量（295 GPa）, 是最硬的化合物, 与先前的理论和实验结果相符. 计算得到的总态密度显示所有结构都具有金属特性. 讨论了系列化合物的变化趋势.

英文摘要：

The structural, thermodynamic, mechanical and electronic properties of 5d transitional metal diborides TMB2 （TM=Hf-Au） are systematically investigated by first-principles within density functional theory. For each diboride, three structures are considered, i.e., AlB2, ReB2 and WB2 structure. The calculated lattice parameters are in good agreement with previous theoretical and experimental results. From the calculated formation enthalpy, thermodynamic stability of compounds is predicted and the formation enthalpy increases from HfB2 to AuB2. Among the considered structures, AlB2 structure is the most stable for HfB2 and TaB2; ReB2 structure is the most stable for WB2, ReB2, OsB2, IrB2 and AuB2; WB2 structure is the most stable for PtB2. The ReB2 in ReB2 structure has the largest shear modulus （295 GPa）, and is the hardest compound, which is in agreement with previous theoretical and experimental results. The calculated density of states shows that they are all metallic. Their variation trends are discussed.