Guerra Juan M, Mahr Carsten, Giar Marcel, Czerner Michael, Heiliger Christian
Institut für Theoretische Physik, Justus-Liebig-Universität (University of Giessen), 35392 Giessen, Germany.
Sci Rep. 2020 Oct 1;10(1):16333. doi: 10.1038/s41598-020-73277-9.
Since there are still research interests in the physical properties of quasi-binary thermoelectric [Formula: see text] alloys, with X, Y = Si, Ge, Sn, we present an ab initio analysis that yields the relative formation energy and effective masses of the conduction bands, in the whole compositional range x. We base our calculations on the full-relativistic Korringa, Kohn and Rostocker (KKR) Green's functions formalism within the coherent potential approximation (CPA). Formation energies, measured relative to the end [Formula: see text] compounds, show no excess energy for the [Formula: see text] substitution thus indicating a complete solubility. In contrast, concave and asymmetric formation energies for intermediate compositions in the [Formula: see text] alloys manifest a miscibility gap. With this basis, we compute and discuss the crossing of the conduction bands observed in n-type [Formula: see text] materials. We present direction- and band-dependent effective masses using a generalized single parabolic band effective mass approximation to discuss anisotropic effects, to interpret available experimental and theoretical data, and to predict intermediate and not yet published transport parameters on these alloys.
由于对准二元热电[化学式：见正文]合金（其中X、Y = Si、Ge、Sn）的物理性质仍有研究兴趣，我们进行了一项从头算分析，得出了整个成分范围x内导带的相对形成能和有效质量。我们的计算基于相干势近似（CPA）内的全相对论性科林加、科恩和罗斯托克（KKR）格林函数形式。相对于终端[化学式：见正文]化合物测量的形成能表明，[化学式：见正文]替代没有多余能量，因此表明完全可溶。相比之下，[化学式：见正文]合金中间成分的凹形和不对称形成能表明存在混溶间隙。在此基础上，我们计算并讨论了在n型[化学式：见正文]材料中观察到的导带交叉。我们使用广义单抛物线带有效质量近似给出方向和能带相关的有效质量，以讨论各向异性效应、解释现有实验和理论数据，并预测这些合金的中间和尚未公布的输运参数。
