Abstract We have investigated the electrical transport properties of the In1-xPbxTe compounds. Small Pb-doping is not incorporated in the In-site but randomly distributed in the matrix from the X-ray diffraction and elemental mapping by energy-dispersive X-ray spectroscopy measurements. The random distribution of Pb elements induces robust charge localization at low temperatures causing the variable range hopping (VRH) transport. The electrical resistivity ρ(T) of pristine InTe exhibits semiconducting to metal transition near 175 K. From the analysis of temperature exponent, we found that the VRH transport is changed from Mott to Efros-Shklovskii (ES) type with decreasing temperature, where the crossover temperatures are found as 14.4 K (x = 0.01) and 13.36 (x = 0.02), respectively. The magnetoresistance (MR) of the InTe shows that the weak antilocalization at low temperature (T ≤ 3 K) and low magnetic field (H ≤ 1 T) competes with weak localization with increasing temperature (T ≥ 5 K). It is noteworthy that small Pb-doping exhibits unconventional negative MR (NMR) behavior because it is not a magnetic or topological material. The unconventional NMR behavior of Pb-doped compounds is attributed to the quantum mechanical interference under the magnetic field in ES type VRH transport. The charge localization crossover from Mott to ES type VRH transport mechanism suggests the strong electron-electron Coulomb interaction in the compounds, leading to the significant change of density of states and inducing the Coulomb gap at low temperatures.

中文翻译：

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In1-xPbxTe 化合物中从 Mott 到 Efros-Shklovskii 型可变范围跳跃机制的电荷定位交叉

摘要 我们研究了 In1-xPbxTe 化合物的电传输特性。通过能量色散 X 射线光谱测量，通过 X 射线衍射和元素映射，少量 Pb 掺杂未并入 In-site 而是随机分布在基体中。Pb 元素的随机分布在低温下引起强大的电荷定位，从而导致可变距离跳跃 (VRH) 传输。原始 InTe 的电阻率 ρ(T) 在 175 K 附近表现出半导体到金属的转变。从温度指数分析，我们发现 VRH 输运随着温度的降低从 Mott 变为 Efros-Shklovskii (ES) 类型，其中交叉温度分别为 14.4 K (x = 0.01) 和 13.36 (x = 0.02)。InTe 的磁阻 (MR) 表明低温 (T ≤ 3 K) 和低磁场 (H ≤ 1 T) 下的弱反局域化与温度升高 (T ≥ 5 K) 的弱局域化竞争。值得注意的是，小 Pb 掺杂表现出非常规的负 MR (NMR) 行为，因为它不是磁性或拓扑材料。Pb 掺杂化合物的非常规 NMR 行为归因于 ES 型 VRH 传输中磁场下的量子力学干扰。从 Mott 到 ES 型 VRH 传输机制的电荷局域化交叉表明化合物中强的电子 - 电子库仑相互作用，导致态密度的显着变化并在低温下诱导库仑间隙。