Defect structure of Sb<sub>2−</sub><em><sub>x</sub></em>Mn<em><sub>x</sub></em>Te<sub>3</sub> single crystals

Incorporation of the transition metal elements in the tetradymite structure of Sb2Te3 has a strong influence on electronic properties. Recent studies have indicated that Mn substitutes on the Sb sublattice increases the carrier concentration of holes. However, the doping efficiency of Mn appears rather low in comparison to what it should be based on the measurements of magnetization, structural analysis, and transport properties. In this paper we address this issue by making detailed studies of the Hall effect and electrical resistivity and we explain the results with the aid of a model that takes into account interactions of the Mn impurity with the native defects in antimony telluride. Specifically, we find that Mn atoms interact with antisite defects (antimony atoms located on the tellurium sublattice), a process that decreases the density of antisite centers and generates free electrons. These, in turn, recombine with holes and thus decrease their concentration and the apparent Mn doping efficiency.

在Sb₂Te₃的辉碲铋矿结构中掺入过渡金属元素对电子性质有很大影响。近期研究表明，锰替代锑亚晶格会增加空穴的载流子浓度。然而，与基于磁化测量、结构分析和输运性质所预期的值相比，锰的掺杂效率显得相当低。在本文中，我们通过对霍尔效应和电阻率进行详细研究来解决这个问题，并借助一个考虑锰杂质与碲化锑中本征缺陷相互作用的模型来解释结果。具体而言，我们发现锰原子与反位缺陷（位于碲亚晶格上的锑原子）相互作用，这一过程降低了反位中心的密度并产生自由电子。这些自由电子反过来又与空穴复合，从而降低了空穴浓度和表观的锰掺杂效率。