Analysis of the resistivity (ρ), thermoelectric power (S), and heat capacity (Cp) of Fe1-xNixSi is presented in this report. In-spite of Ni having two extra valence electrons as compared to Fe, the physical properties are observed to be dominated by holes. In this report, we have explained this unusual hole dominant scenario by a modified two narrow-band model. According to this model, the impurity electrons which are nearer to conduction band get shifted towards lower energy level thereby leaving holes around the Fermi level, and hence a hole dominated scenario at low temperatures. Due to this hole like density of states around the Fermi level, the nickel substitution could only produce a weak ferromagnetic behaviour. Such a picture may assist in understanding the thermopower of similar systems i.e. Ni substituted on Fe site, such as Fe2-xNixVAl. We have also found that the activation energy derived from resistivity and thermoelectric power decreases with increasing Ni concentration.

中文翻译：

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Ni 取代 FeSi 中的非常规杂质能带导通和载流子动力学


本报告介绍了 Fe1-xNixSi 的电阻率 (ρ)、热电势 (S) 和热容 (Cp) 的分析。尽管与 Fe 相比 Ni 具有两个额外的价电子，但观察到其物理性质以空穴为主。在本报告中，我们通过修改后的两窄带模型解释了这种不寻常的空穴主导情况。根据该模型，靠近导带的杂质电子向较低能级移动，从而在费米能级周围留下空穴，因此在低温下出现空穴主导的情况。由于费米能级周围存在类似空穴的态密度，镍替代只能产生弱铁磁行为。这样的图片可能有助于理解类似系统的热电势，即 Ni 取代 Fe 位点，例如 Fe2-xNixVAl。我们还发现，电阻率和热电势产生的活化能随着镍浓度的增加而降低。