Department of Physics, University of California, Berkeley, California 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2016 Feb 19;116(7):077201. doi: 10.1103/PhysRevLett.116.077201. Epub 2016 Feb 18.
The current density j^{B} induced in a clean metal by a slowly-varying magnetic field B is formulated as the low-frequency limit of natural optical activity, or natural gyrotropy. Working with a multiband Pauli Hamiltonian, we obtain from the Kubo formula a simple expression for α_{ij}^{GME}=j_{i}^{B}/B_{j} in terms of the intrinsic magnetic moment (orbital plus spin) of the Bloch electrons on the Fermi surface. An alternate semiclassical derivation provides an intuitive picture of the effect, and takes into account the influence of scattering processes in dirty metals. This "gyrotropic magnetic effect" is fundamentally different from the chiral magnetic effect driven by the chiral anomaly and governed by the Berry curvature on the Fermi surface, and the two effects are compared for a minimal model of a Weyl semimetal. Like the Berry curvature, the intrinsic magnetic moment should be regarded as a basic ingredient in the Fermi-liquid description of transport in broken-symmetry metals.
在清洁金属中，由缓慢变化的磁场 B 感应出的电流密度 j^{B}可以表述为自然旋光性或自然旋磁性的低频极限。通过使用多带 Pauli 哈密顿量，我们从 Kubo 公式推导出一个简单的表达式，用于表示 Bloch 电子在费米表面上的固有磁矩（轨道加自旋）与 GME 系数 α_{ij}^{GME}=j_{i}^{B}/B_{j}之间的关系。另一种半经典推导提供了对该效应的直观描述，并考虑了在粗糙金属中的散射过程的影响。这种“旋磁性磁效应”与由手征反常驱动并由费米表面上的 Berry 曲率控制的手征磁场效应在根本上不同，我们对 Weyl 半金属的最小模型进行了这两种效应的比较。与 Berry 曲率一样，固有磁矩应被视为在破对称金属中输运的费米液体描述的基本成分。
