论文标题
杂质和分散效果对量子极限中线性磁化的影响
Impurity and dispersion effects on the linear magnetoresistance in the quantum limit
论文作者
论文摘要
磁磁性，即使用磁场的电阻的变化通常是场强的二次函数。线性磁置通常会揭示系统的非凡特性。在仅占据最低兰道带的量子极限中，据信量子线性磁磁性是具有3D线性分散体的Weyl费米子的标志。在这里，我们相对研究具有不同带分散的系统以及不同类型的杂质的量子限值。我们发现，对于二次能量分散，磁磁性也可以是线性的。我们表明，如果远距离高斯型杂质占主导地位，纵向和横向磁磁性都可以是线性的，但是库仑型杂质只能诱导线性横向磁路线。此外，由于线性分散体和散射机制的综合效应，无论杂质类型如何，我们都发现无质量的dirac费米子中的负纵向磁磁性。我们的发现很好地解释了在实验中观察到的一些线性磁化，并为理解量子限制磁路线的理解提供了见解。
Magnetoresistance, that is, the change of the resistance with the magnetic field, is usually a quadratic function of the field strength. A linear magnetoresistance usually reveals extraordinary properties of a system. In the quantum limit where only the lowest Landau band is occupied, a quantum linear magnetoresistance was believed to be the signature of the Weyl fermions with 3D linear dispersion. Here, we comparatively investigate the quantum-limit magnetoresistance of systems with different band dispersions as well as different types of impurities. We find that the magnetoresistance can also be linear for the quadratic energy dispersion. We show that both longitudinal and transverse magnetoresistance can be linear if long-range-Gaussian-type impurities dominate, but Coulomb-type impurities can only induce linear transverse magnetoresistance. Moreover, we find a negative longitudinal magnetoresistance in massless Dirac fermions, regardless of the impurity type, as a result of the combined effect of the linear dispersion and the scattering mechanism. Our findings well explain some of the linear magnetoresistance observed in the experiments and provide insights to the understanding of quantum-limit magnetoresistance.
