Condensed Matter Theory Laboratory, RIKEN, Saitama, Japan.
Phys Rev Lett. 2011 Jun 10;106(23):236402. doi: 10.1103/PhysRevLett.106.236402. Epub 2011 Jun 9.
Transport in an ideal two-dimensional quantum spin Hall device is dominated by the counterpropagating edge states of electrons with opposite spins, giving the universal value of the conductance, 2e(2)/h. We study the effect on the conductance of a magnetic impurity, which can backscatter an electron from one edge state to the other. In the case of isotropic Kondo exchange we find that the correction to the electrical conductance caused by such an impurity vanishes in the dc limit, while the thermal conductance does acquire a finite correction due to the spin-flip backscattering.
在理想的二维量子自旋霍尔器件中，电子的反传播边缘态主导着输运，其电导具有普适值 2e(2)/h。我们研究了磁性杂质对电导的影响，该杂质可以将电子从一个边缘态反向散射到另一个边缘态。在各向同性的 Kondo 交换情况下，我们发现这种杂质引起的电导率修正在直流极限下消失，而热导率由于自旋反转的反向散射确实会获得有限的修正。
