Abstract The quaternary chalcogenides, attracting much attention in recent time as promising solar energy materials, permit an effective optimization of their composition by the Ge incorporation. In particular, this implies an interest to the Cu2ZnGeS4 compound, which utilization requires, however, a deeper understanding of its electronic properties in general. Here, we investigate magnetotransport of the p-type Cu2ZnGeS4 single crystals, including resistivity, ρ (T), magnetoresistance (MR) and Hall effect, in pulsed magnetic fields up to B = 20 T. The Mott variable-range hopping charge transfer has been established within a broad temperature interval of T between ∼100 and 200 K by investigations of ρ (T) in zero field. The positive and negative contributions to MR have been observed, attributing them to shrinkage of the impurity wave functions by the magnetic field and to the destructive interference of the hopping charge carriers, respectively. Observation of the negative Hall coefficient, RH (T), exhibiting the dependence close to that of ρ (T), gives a strong support to the Mott conduction mechanism in our p-type Cu2ZnGeS4 material. In addition, the conductivity, connected with thermal activation of holes on the mobility edge, Ec, has been identified both below and above the Mott conduction interval. Finally, the joint analysis of the ρ (T) and MR data has yielded a series of important microscopic parameters. These include such details of the hole spectrum in the acceptor band, as its semi-width, W, the density of localized states, g (μ), at the Fermi level, μ, the positions of μ and Ec, as well as values of the localization radius of holes, a, and of the acceptor concentration, NA.

中文翻译：

---

Cu 2 ZnGeS 4 单晶中的高场磁传输

摘要 四元硫属化物作为一种有前途的太阳能材料，近年来受到广泛关注，它允许通过掺入 Ge 来有效优化其组成。特别是，这意味着对 Cu2ZnGeS4 化合物的兴趣，然而，使用这种化合物需要对其电子特性有更深入的了解。在这里，我们研究了在高达 B = 20 T 的脉冲磁场中 p 型 Cu2ZnGeS4 单晶的磁传输，包括电阻率、ρ (T)、磁阻 (MR) 和霍尔效应。 Mott 可变范围跳跃电荷转移具有通过在零场中对 ρ (T) 的研究，在 ~100 和 200 K 之间的 T 的宽温度区间内建立了。已观察到对 MR 的正负贡献，将它们分别归因于磁场引起的杂质波函数的收缩和跳跃电荷载流子的相消干涉。观察到的负霍尔系数 RH (T) 表现出与 ρ (T) 接近的依赖性，有力地支持了我们 p 型 Cu2ZnGeS4 材料中的莫特传导机制。此外，在 Mott 传导区间的下方和上方都确定了与迁移率边缘 Ec 上空穴的热激活相关的电导率。最后，通过对 ρ (T) 和 MR 数据的联合分析，得出了一系列重要的微观参数。这些包括受主带中空穴光谱的详细信息，如其半宽度 W、局域态密度 g (μ)、费米能级 μ、μ 和 Ec 的位置，