Accurate descriptions of the structure, electronic properties and thermoelectric (TE) properties of transition-metal nitride halides MNBr (M = Zr, Hf) monolayers are calculated using the full-potential linearized augmented plane-wave (FP-LAPW) method within both generalized gradient approximation (GGA) and Tran–Blaha modified Becke–Johnson (TB-mBJ) approximation. The band structure shows that all MNBr monolayers are semiconductors with indirect band gaps. The band gap, calculated by TB-mBJ, is larger than that of GGA for both considered compounds. The charge-carrier effective mass increases when going from ZrNBr to HfNBr because of the extra peak of the density of states profile of monolayer HfNBr in the valence band around −0.5 eV, suggesting that ZrNBr should have higher electrical conductivity and HfNBr should have higher Seebeck coefficient. Meanwhile, the monolayered structure of MNBr has intrinsic low lattice thermal conductivity. The results demonstrate that monolayer MNBr has interesting TE properties with n-type doping.

使用全电位线性增强平面波 (FP-LAPW) 方法计算过渡金属氮化物卤化物 MNBr (M = Zr, Hf) 单层的结构、电子特性和热电 (TE) 特性的准确描述。梯度近似 (GGA) 和 Tran-Blaha 修正的 Becke-Johnson (TB-mBJ) 近似。能带结构表明所有 MNBr 单层都是具有间接带隙的半导体。对于两种考虑的化合物，由 TB-mBJ 计算的带隙大于 GGA 的带隙。当从 ZrNBr 到 HfNBr 时，电荷载流子有效质量增加，因为价带中单层 HfNBr 的态密度分布的额外峰值在 -0.5 eV 附近，这表明 ZrNBr 应具有更高的电导率，而 HfNBr 应具有更高的塞贝克系数。同时，MNBr 的单层结构具有固有的低晶格热导率。结果表明，单层 MNBr 具有有趣的 n 型掺杂的 TE 特性。