Embedding isoelectronic and isostructural XTe (X = Ca, Sr, Ba) compounds in Na-doped PbTe can significantly boost thermoelectric performance through interface engineering and phonon scattering. Thus, defects in PbTe-based compounds play an essential role in improving the thermoelectric properties. In this study, we investigate the formation energies of charged intrinsic and extrinsic (Na) defects in a PbTe/PbXTe/XTe pseudo-interface. We find that different synthesis conditions of PbTe uniquely determine the lowest-energy defects. The low formation energies of ${\text{Na}}_{\text{Sr}}^{1-}$ (and ${\text{Na}}_{\text{Pb}}^{1-}$) play an important role in increasing the Na concentration in the solid solution PbTe/SrTe interface, in good agreement with the experimental observations. A low energy Na charged defect (n-type ${\text{Na}}_{\text{Te}}^{3+}$) has been distinctly identified in the PbXTe solid solutions as well. Thus, the defect should be eliminated in the SrTe precipitated PbTe system for the p-type purpose. However, if experiments could synthesize the Pb_0.5Sr_0.5Te solid solution ingot, ${\text{Na}}_{\text{Te}}^{3+}$ will play an important role to achieve the n-type behavior. While low energy defects have little effect on the electronic structures in PbTe and XTe, they enhance the density of states around the Fermi level in PbXTe solid solutions. Our work therefore not only elucidates the lowest energy defects in PbTe-based materials, but it also paves the way to understanding and designing promising thermoelectrics with interface phases.

将等电子和等结构的XTe（X = Ca，Sr，Ba）化合物嵌入掺Na的PbTe中可以通过界面工程和声子散射显着提高热电性能。因此，基于PbTe的化合物中的缺陷在改善热电性能方面起着至关重要的作用。在这项研究中，我们研究了PbTe / PbXTe / XTe伪界面中带电的本征和非本征（Na）缺陷的形成能。我们发现，PbTe的不同合成条件唯一确定了最低能量的缺陷。的低形成能${\text{娜}}_{\text{r}}^{\mathrm{1个}-}$ （和 ${\text{娜}}_{\text{铅含量}}^{\mathrm{1个}-}$）在增加固溶体PbTe / SrTe界面中的Na浓度中起重要作用，与实验观察结果非常吻合。低能Na带电缺陷（n型${\text{娜}}_{\text{特}}^{3+}$）在PbXTe固溶体中也得到了明确识别。因此，应在SrTe沉淀PbTe系统中出于p型目的消除缺陷。但是，如果实验可以合成Pb _0.5 Sr _0.5 Te固溶体锭，${\text{娜}}_{\text{特}}^{3+}$将对实现n型行为起重要作用。尽管低能缺陷对PbTe和XTe中的电子结构影响很小，但它们提高了PbXTe固溶体中费米能级附近的态密度。因此，我们的工作不仅阐明了基于PbTe的材料中的最低能量缺陷，而且还为理解和设计具有界面相的热电学铺平了道路。