Origin of the energy gap in the narrow-gap semiconductor FeSb2 revealed by high-pressure magnetotransport measurements
Origin of the energy gap in the narrow-gap semiconductor FeSb2 revealed by high-pressure magnetotransport measurements
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DOI：
10.1103/physrevb.88.165205
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发表时间：
2013-10-24
影响因子：
3.7
通讯作者：
Yasui, Y.
中科院分区：
文献类型：
--
作者：
Takahashi, H.;Okazaki, R.;Yasui, Y.
为了阐明窄禁带半导体FeSb 2中两个能隙的起源，我们研究了流体静压对低温下电阻率、霍尔电阻和磁阻的影响。从温度依赖性的电阻率高于100 K的更大的能隙评估增强从30至40毫电子伏的压力从0到1.8 GPa，一般在传统的半导体中观察到的。在低温范围内，观察到一个大的塞贝克系数，我们评估的磁输运张量使用两个载流子模型的较小的能隙，并发现较小的差距表现出较弱的压力依赖性相比，较大的差距。为了解释能隙的压力变化，我们提出了一个简单的模型，即较小的间隙是从杂质能级到导带的间隙，较大的间隙是价带和导带之间的间隙，这表明所观察到的大Seebeck系数与电子相关效应无关。
To elucidate an origin of the two energy gaps in the narrow-gap semiconductor FeSb2, we have investigated the effects of hydrostatic pressure on the resistivity, Hall resistance, and magnetoresistance at low temperatures. The larger energy gap evaluated from the temperature dependence of resistivity above 100 K is enhanced from 30 to 40 meV with pressure from 0 to 1.8 GPa, as generally observed in conventional semiconductors. In the low-temperature range where a large Seebeck coefficient was observed, we evaluate the smaller energy gap from the magnetotransport tensor using a two-carrier model and find that the smaller gap exhibits a weak pressure dependence in contrast to that of the larger gap. To explain the pressure variations of the energy gaps, we propose a simple model that the smaller gap is a gap from the impurity level to the conduction band and the larger one is a gap between the valence and conduction bands, suggesting that the observed large Seebeck coefficient is not relevant to electron correlation effects.