论文标题
第一原理研究结构障碍，现场偏好，化学键合和掺杂的四面体的转运特性
First-principles study of structural disorder, site preference, chemical bonding and transport properties of Mg-doped tetrahedrite
论文作者
论文摘要
基于四面体的（$ \ textrm {Cu} _ {12} \ textrm {sb} _ {4} \ textrm {s} _ {13} $）是良好的热电发生器的候选材料，这是由于其内在的，非常低的热电导率和高功率和高功率因素而引起的。目前的局限性之一是缺乏表现出N-型电导率的四面体。在这项工作中，进行第一原则计算以研究MG掺杂的四面体，$ \ textrm {mg} _ {x} \ textrm {cu} _ {12} \ textrm {sb} _ {sb} _ {4} _ {4} \ textrm {sbextrm {s}研究了结构的不同浓度和修饰，以表明其形成能量，首选地点职业以及掺杂剂周围的当地环境变化。 Mg原子倾向于占据6B位点，而引入过量的Cu更喜欢24G位点。这些站点中元素的引入对附近的Cu（2）原子显示出不同的影响。拓扑分析表明，四面体表现出具有一定程度的共价的离子封闭键。大多数债券随着MG含量的增加而削弱了；结构变得越来越不稳定，这也由全球不稳定性和键菌株指数表达。通过$ x> 1.0 $的结构的计算，可以预测N-type电导率，但是形成和缺乏稳定性的焓增加可能表明溶解度的限制和难以通过实验获得这些限制。
Tetrahedrite-based ($\textrm{Cu}_{12}\textrm{Sb}_{4}\textrm{S}_{13}$) materials are candidates for good thermoelectric generators due to their intrinsic, very low thermal conductivity and high power factor. One of the current limitations is virtual absence of tetrahedrites exhibiting n--type conductivity. In this work, first-principles calculations are carried out to study Mg-doped tetrahedrite, $\textrm{Mg}_{x}\textrm{Cu}_{12}\textrm{Sb}_{4}\textrm{S}_{13}$ with possibility of predicting n--type material in mind. Different concentrations and modifications of the structure are investigated for their formation energies, preferred site occupation and change in local environment around dopants. Mg atoms tend to occupy 6b site, while introduced excess Cu prefers 24g site. Introduction of elements in those sites display different effect on nearby rattling Cu(2) atom. Topological analysis shows that tetrahedrite exhibits ionic, closed-shell bonds with some degree of covalency. Majority of the bonds weakens with increasing content of Mg; structure becomes increasingly less stable, which is also expressed by global instability and bond strain indexes. Achieving n--type conductivity was predicted by the calculations for structures with $x>1.0$, however increasing enthalpy of formation and lack of stability might suggest limit of solubility and difficulties in obtaining those experimentally.
