Abstract The combined powder X-ray diffraction, microstructural, local and bulk chemical analyses of natural pyrite single crystals from Reiche Zeche, Johangeorgenstadt and Pretzchendorf (Erzgebirge, Saxony, Germany) showed compositions FeAs0.002(1)S1.998(9), FeAs0.004(1)S1.996(9) and FeAs0.005(1)S1.995(9), respectively. The arsenic doping leads to smaller semiconducting energy gaps (Eg ∼0.1–0.2 eV) in comparison with binary FeS2 (Eg = 0.96 eV), as well as switching of conduction type mechanism from n-to the p-type. These findings are supported by the measurements of the electrical resistivity and Seebeck coefficient of the synthetic FeAsxS2-x series (maximal As-content x = 0.01 at 773 K). The investigations of sintered FeS2 + MO2 (M = Si, Ti, Zr) composites indicate that some insulating metal oxides as impurities influence less the electrical transport properties of pyrite. All performed studies unambiguously confirmed that p-type conductivity for T > 300 K is a hallmark of the ternary As-doped FeAsxS2-x (x ≥ 0.002) pyrites.

中文翻译：

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天然和合成 FeAs S2- (x ≤ 0.01) 的电和热传输特性

摘要 来自 Reiche Zeche、Johangeorgenstadt 和 Pretzchendorf（Erzgebirge，Saxony，Germany）的天然黄铁矿单晶的粉末 X 射线衍射、微观结构、局部和整体化学分析的组合显示成分为 FeAs0.002(1)S1.998(9)，分别为 FeAs0.004(1)S1.996(9) 和 FeAs0.005(1)S1.995(9)。与二元 FeS2 (Eg = 0.96 eV) 相比，砷掺杂导致更小的半导体能隙 (Eg ∼0.1–0.2 eV)，以及导电类型机制从 n 型到 p 型的转换。这些发现得到了合成 FeAsxS2-x 系列电阻率和塞贝克系数的测量结果的支持（最大 As 含量 x = 0.01 在 773 K）。烧结 FeS2 + MO2 (M = Si, Ti, Zr) 复合材料表明，一些绝缘金属氧化物作为杂质对黄铁矿的电传输性能影响较小。所有进行的研究都明确证实 T > 300 K 的 p 型电导率是三元 As 掺杂的 FeAsxS2-x (x ≥ 0.002) 黄铁矿的标志。