Carrier transport in Mg₂Si_1-xSn_x thermoelectrics was experimentally found to be highly sensitive to high temperature heat treatment and in particular the role of the precise Mg content has been discussed controversially. Considering this, electrical transport properties of Sb doped Mg₂Si_0.4Sn_0.6 were measured in-situ during annealing at 710 K. We measured two quasi-identical samples: sample 1, for the Seebeck coefficient and the electrical conductivity ($\sigma$) measurement in helium, and sample 2 for Hall coefficient and $\sigma$ measurement in vacuum, respectively. Both samples largely remain single phase and did not show de-mixing after annealing for $\sim$276 hours and $\sim$1100 hours respectively. The observed experimental data can be modelled using a single- and two parabolic band model and a continuous reduction in majority carriers is identified, which can be linked to Mg loss. Thorough analysis furthermore reveals mobility loss and a lowering of the density of states effective mass which could both be due to ongoing Mg loss or due to a lifted degeneracy of conduction bands in Mg₂Si_0.4Sn_0.6 at room temperature. Finally, we can link the change in carrier concentration to a change in Mg-related defects and identify a phase width $\delta$δ in Mg_2-δSi_0.4Sn_0.6.

实验发现，Mg ₂ Si _{1- x} Sn _x热电材料中的载流子传输对高温热处理高度敏感，尤其是精确的 Mg 含量的作用已引起争议。考虑到这一点，在 710 K 退火期间原位测量了 Sb 掺杂的 Mg ₂ Si _0.4 Sn _{0.6 的}电传输特性。我们测量了两个准相同的样品：样品 1，用于塞贝克系数和电导率（$\sigma$) 在氦气中测量，霍尔系数和样品 2 $\sigma$分别在真空中测量。两个样品在很大程度上保持单相并且在退火后没有出现分层$～$276 小时和 $～$分别为1100小时。观察到的实验数据可以使用单抛物线带模型和双抛物线带模型进行建模，并且可以识别出多数载流子的持续减少，这可能与镁损失有关。彻底的分析进一步揭示了迁移率损失和有效质量态密度的降低，这可能是由于持续的 Mg 损失或由于室温下Mg ₂ Si _0.4 Sn _0.6中导带简并性的提高。最后，我们可以将载流子浓度的变化与 Mg 相关缺陷的变化联系起来，并确定相宽度$\delta$Mg _2-δ Si _0.4 Sn _{0.6 中的δ}。