Corrections to the magnetoresistance formula for semimetals with Dirac electrons: the Boltzmann equation approach validated by the Kubo formula
Corrections to the magnetoresistance formula for semimetals with Dirac electrons: the Boltzmann equation approach validated by the Kubo formula
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DOI：
10.1088/1361-648x/aae03c
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发表时间：
2018-10
期刊：
影响因子：
--
通讯作者：
M. Owada;Yudai Awashima;Y. Fuseya
中科院分区：
文献类型：
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作者：
M. Owada;Yudai Awashima;Y. Fuseya
基于玻耳兹曼理论，研究了含有Dirac(或Weyl)电子和自由空穴的半金属材料的磁阻效应。由于狄拉克色散的修正，MR以一种非常复杂的方式从传统的含有自由电子和空穴的结果修正而来。所得到的公式明确地包含了磁场的依赖关系，这对于分析实验结果是非常有用的。为了验证我们结果的有效性，用Boltzmann方法得到的结果与用Kubo理论得到的结果进行了比较。结果表明，考虑到载流子密度对场的依赖关系，即使在高场区(量子极限)，由Boltzmann理论得到的MR与基于Kubo理论的MR几乎完全一致，但量子振荡除外。结果还表明，由于载流子密度的急剧变化，半金属中的MR相对于量子极限中的场呈线性增加，这是半金属的一个重要特征。
The magnetoresistance (MR) in semimetals with Dirac (or Weyl) electrons and free holes is investigated on the basis of the Boltzmann theory. The MR is modified from the conventional results with free electrons and holes in a very complex way due to the correction of the Dirac dispersion. The obtained formula explicitly includes the magnetic field dependence, which is very useful for the analysis of experimental results. In order to verify the validity of our results, the results obtained by the Boltzmann approach are compared with those by the Kubo theory. It is revealed that, by taking into account the field dependence of carrier density, the MR obtained by the Boltzmann theory almost perfectly agrees with that based on the Kubo theory even in the high-field region (in the quantum limit) except for the quantum oscillations. It is also shown that the MR in semimetals increases linearly with respect to the field in the quantum limit due to the drastic change of the carrier density, which is a significant characteristic of semimetals.